Instruction Manual Models:1770/1775/1780 Linear Programmable Power Supplies NTABLE OF CONTENTS ONE Ll 1.2 1.3 1.4 1.5 1.6 TWO 2.1 2.2 2.3 THREE 3.1 3.2 3.3 3.4 3.5 3.6 FOUR Al 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 INTRODUCTION De@SCiption. 2... cece ceceeeecsesseseeesesssessssesssuestassrsasssssusevavevaverevsstatatssitisseasissiesticiviveveveceseeeeece. 1 IMSPeCtiOn......... sees sseseessseseseetesssssssssstessssessssusansvsssusavavevsvessusavasasasusisitatstssacesecavevevaveveveceeee. 1 Included Ttemss...... ccc ceeeesceseescessecsessscsnscevsvssesessvessuavevesasavavevstatsavsvesieusvevevevecesettetetceeecccs. 1 Cautions And Warnings... cececccccccseesesseseesesscscessrssessvssssssvsssevsutstavatatstasssitavststsitevevseseeseeseses 1 Location And Cooling... cc ccecccecesesseseescsescsssscsvsssnsacssssusavevauavavasasasatatavavaviceviveveuevevevatevecees 2 GPIB Interface Connector... eccececscscsessesesssussvsvsscsssvsvsvevsusavstavsvevevevasavasaveveveveveveveveeseetececee. 2 GETTING STARTED Unit Familiarization. 2... ccc ccccccccscsesesssesvesesessuvscssssstacecseavassessneaasssstsesevavacscresvevaveveseseeveseeees 3 2.1.1 Front Panel Keys oo... ceecccccccccesscssscssscseuscsevscscsssevesausesavavasassassasassatstvecsevavasetteveceeceeeess 4 2.1.2 Rear Pamed. oie i ccecceccccscsessseseescesecssscecessensuscesauseessaatsssavavssvassavstatsasssvsvitsvevesteveseeseeeess 7 LCD Status Ammunciators,..........cccccccccccccscscscscsesssssssesssececsavsuevavstevassvssvevasavetscesusvevevevevteetececeees 7 Output Terminals And Wires oo... ccsessssesesesessscscsssessacsssssesesieseassevavssssstvasavatevesseeseavesees 8 Trntrod ction... ecececcecccesesesesesesesesessvsvevssssassusscesavssssavavesseraneveussesssssituevavausseveveveveveveceeteveeees 10 Operating Ranges... cececceccscsssssesssecscscsesesccscsvsvsvsceveevsvsssnvasatatarsavatvass savserevatsvitevteeveseeceeeees 10 Remote Sense... .c.ccecccecsceesesesesesesescsesassesessvsssussvacscacacacsevsvevaverevavasaeassevavaasetveveveveciveceseeveeess 11 3.3.1 Remote Sense Configuration........0.0..cccccccccesecsesesseeveseevsseseaevscssesssevsssesessvesistscesteeseesess il 3.3.2 Remote Sense Characteristics..0.0........ccccccccccecccessseececevevssssseceensssesevausevaseccevsvstesessveseeeees 11 Load Consideration And Multiple Loads Commection .0......0.c..cccccccsssccsescseeecsesecssecesssescesceseeseeces 12 Parallel Connection Operation. ....0.0..c.cccccccceccscecececseeveceecsecseecasuecetasvesesssevessisvetevessecesceeeecee: 13 3.5.1 CV Operation... cc cccscccsessnessescsesesceesscsesceseesevssvevevavavsusavaesavetsatstievassevavseevesseeaseaees 14 3.5.2 CC Operation... cccceescscsesscscsessecscsescstecscnevsvavssesstatsssssatasstsassevasssvevstitesvaceseesersecs 14 3.5.3 Remote Sensing Configuration (Parallel Connection Mode)........0.c.cccccccscsssssseevecececeeseseees 14 Series Connection Operation ..0.0......cccccccccccscscsssessscssssvscsvscavsveveseatavatatasssstasacssesevavsvaveveeseseevace 15 3.6.1 CV Operation... ccc cccccceescscseevessssseeessuevesrsssvstsvssscassvassesevavatatstssvavasststststeseevecenvees 15 3.6.2 CC Operation... eee ecceeecceeseesesssesessceeuesessususcsvevsvevevesevsvesaesevavevavataeaseevataveveseveeseeenes 15 3.6.3 Remote Sense Configuration (Series Connection Mode)...0....0.ccceccccccccsecsececesessecseseeseseeees 16 LOCAL OPERATION TtrOUetion. o.oo eee ccecesesescseeseecsssesevasssessssceesscscsessvavavacesvassusavavssaesatsastatvatstvatssesvavavesvatseeeees 17 General Information... ccccccccecsescsscecscececcevsveseeveveveessveseusersvatsevassstsessvassevevisvevevasiseitvesees 17 Setting Voltage... ec cccceesesesssesesesesesesesesescsessssscseseseeevevsvscstsvevesevsaseavasatatsssesvavavsvenevecsess 17 Setting Current... cccccccsesssssevessssssssceseecsesssessvsvevsevssrevsvevavesaesassevassevatisvavasvevecisisvseiseseesves 18 Setting The Protection Modes..........c.ccccccccccccsssssssescsssssuscuevevevecevecevscsevesavssavssstsevasavavevanseesvensees 19 4.5.1 Setting The Overvoltage Threshold..........0...cccccccccccccecsssessetesesesvscseseeevevevseesstattsevsvesseeees 19 4.5.2 Enabling/Disabling Overvoltage Protection. .....0000.0..0.ccccccccccceceseeccssesesaceceecstecstvecescvessees 19 4.5.3 Enabling/Disabling Overcurrent Protection. .......0.0.0.000ccccceccescesesescesesesesecessttevevseveveteseses 19 Enabling/Disabling Outputs....00.00.. cc cccccccsccccescecssesescsevestesssseseusvsesvaesssesseaserssvstestesavesensevaesaes 20 Tracking Operation Models:1775/1780).......0.00.cccccsecscccecesecsesesvscessessravatertacesecsevatavstesteteetvssess 20 Range Operation (Model 1770)... ccccccccccccscscsscnscseesseeverecessavsevsesssvststssvseststseviceeveresesees 20 Audible Signal...........scscceee. sees sovsesesscsosivesssnetassesearessasuuvssisasissssseessessnitssritsssiesssieseaesareeee 20FIVE 5.1 5.2 5.3 5.4 3.5 5.6 SIX 6.1 6.2 6.3 6.4 6.5 SEVEN 71 7.2 73 EIGHT GAWD Pp NINE REMOTE OPERATION I Est une TsC0 Ce] 6 Ce): eee ESEEESOOOOESECOES OO OOSOOOOOOCOOOOOOOOOOSS 21 GPIB Operation..........cceeec eect seers csesceeceeseseseeceesneeecaeenesssensenesseesnenecssereensesecenscrssensaeseres eset: 22 .2.1 GPIB Interface Functions. ...0....0ccccccccceeceeeeereeeeee certs ceeeenesenneeeeceeeeeneeteneennee eens aaeeaeersenegs 22 5.2.2 Address Setting Of GPIB Interface... ccc eccccecee eee e eee teeen ee cee eee tees ereeetentnerenerreceiantas 22 Programming Syntax........c.cccceccccceseesssesesceseecseseeeneneeseesessenecseseneressenesesecseseseenecareeceeeeenenenenn segs 23 5.3.1 GPIB Device Commands List... cece eee eter teeeeenies sseueesscececucececaseseenteecensatersaets 23 ,3.2 Calibration Commands. ..........cccccccccccceeeeeee cee eer eee tenee een ee eee ee renner eee e enna s ater ener EERE eee enn aeS 24 Status Reporting. .......ccccec ccc ee esse seeseenseeseneecteeeeeeeerecesecsnecsessssssseessecsersasacnerenseresisarecetensaseess 24 Programming The Power Supply...........cccccccecececeee reeset esererers essere cenesee neces reneneeeseeseseeeee gees 25 5.5.1 Output ON/OFF... cece eect cee ees eeeeeeeceereeees tees reeseeseseeranenceeerneneset tessa nearer esse eas 26 5.5.2 Voltage Programming. ..........ccececccccecsene crete rer tene sree ree esereeenneneeneenennene teen raeeenee ene tgay 26 5,5.3 Overvoltage Programming (Ovset)..0.....ccccccceeseeeteeeeeete rete cee esetesteneeessesseeseerertaereseeas 26 5.5.4 Current Programming... eee cee cee cee e ten tener eects cesenee nee reeenee rns eeeeetnareeneeneeneneris tas 27 5.5.5 Overcurrent Protection (OCp).........c.cccceceee eee eee een eete cent enee ere e ern e nese eee a tne ee nee eee ennt egies 27 SBR SMe Wo (o) a 0s 100 051-11 (6 ROO EEE EEIEOS OOS COOOOCOOOOOOOOOOOOOOOOOOOOOOOOSIO 28 Fundamentals Of Programming. .............:ccecccceecscesseene ener reer eee nee eres e earners esanteenarestenneennt ens 28 CALIBRATION I TeLacoYe hI Cel (0) s pena PEESOO EO ETSTECESESSSOOOOSOOOSOOOOOOOOOOOROOOOOCOOOOSS 31 Calibration Comfiguration.............ccceceeesceceesecenecneeeeneeneene tae raenee sense teeseasssenseneeaeseenneereesnaneegegs 31 Local Calibration......c...ccccccccccccssccsseeccnsseeeeeeseeereeeenseeseneeensasectereeeenaneernieecenneeesseeseeeesnnesesieeees 32 RemoteCalibration. 0.0.2.2... cccccccccccesecseceeeenseeceeccneeceeseeeeeteesaeeeeeeeaeneeeneeneneeeeeeenersaseeesereereniseeenenaes 33 Calibration Program Example...........ccccccecce reece teen eeeeneeretnaes eeceuessetsavsusecsneseeteeaneseseeee 33 USER MAINTENANCE/SERVICE Fuse Replacement ..........ccccccecse cece ceeeene ese ne eens tec nee cn eee ne ened Seen EERE EES eee S een 34 In Case Of Difficulties. ...0.....c cc eccccccecesceceeeceeeceeeereeteeen ee eeneneeeeneernegaeeeestenaeesestanennneaeeeceneneaeees 34 Warranty Information... ccc cecccceteccee ee eeeteeeeeseneraeseneeessssenenecenesaarenenacessses eases seen se nene ngs 35 Shipping Instructions...........0.c:ceccccceeceeeeecseeeseeceeeeerenenesasseeeneeneneneeasnensnenenenceseesser essa eeee geste 36 APPENDICES Specification (continued)... ccc cece screens et iee eter eeeseneesscnenseaneeisecscersessssenesrssstessceseatesgsty 37 Command Summa rics...........cccccccccscccceccecseeecceeceeeeessneeeaeeeeeeseeareeeneneeetenseesersseeeessaesereneensgees 4] Query MeSsages........c.ccccccsescsceeseseeeseseeenesesceceesseeaeaeesessesesnsnssssecsessnseeneneneeasenesisicaseestsseesennsisegegs 43 Calibration Program Example... cccccsscccceseseneceeereeeeeeeeseenseneseneeersetaeseaneenees cress eases stents 44 SAFETY INFORMATION Safety Information.......0.0..cecececeeesececesceneneeeeeeeiceeerersenerseseencnsasnecesaeeenanecesseseeeee sees sen gee seet ree 45 Mild itaONE: INTRODUCTION Congratulations! You have just purchased one of the most advanced professional Programmable Power Supplies available. The innovative ergonomic design and overall high quality will provide years of reliable operation. Therefore, it is very important to completely familiarize yourself with the unit before attempting use. Please read this manual carefully, paying particular attention to the Warning and Caution sections, 1.1 DESCRIPTION The Programmable Power Supply Series from B+K Precision offers a complete solution to power supply system requirements. These models are indispensable instruments in assisting in the development and testing of new products, as well as being standard instruments for automatic test systems. The wide range of output selection combined with excellent load/line regulation creates a vital instrument in your lab environment. Each supply comes standard with a GPIB interface and a three-year warranty. Plus, all units feature output voltage and current programming, overvoltage and overcurrent protection, remote sense, reverse polarity protection and output enable/disable. All models of the programmable power supply series are able to be calibrated either in local or remote mode. 1.2 INSPECTION When you unpack your new programmable power supply from its ori ginal packaging, carefully check each item for damage that may have occurred during shipment. If the shipping carton is damaged contact the carrier immediately. If anything is missing, please contact B+K Precision at 714-237-9220 for immediate service. 1.3 INCLUDED ITEMS Programmable Power Supply Operation Manual Power Cord 1.4 CAUTIONS AND WARNINGS 1. The input power requirements for the programmable power supplies are 115/230 VAC ~ 10% or 240VAC +5% ~ -15%, 50/60 Hz. 2. Before begin to operate the power supply, set the correct voltage 115 or 230 (240) VAC setting equal to the applied voltage, otherwise damage will result to the power supply . 3. Do not use solvents or aromatic hydrocarbons to clean the module as they may damage the finish. If cleaning is necessary, use only a mild solution of soap and warm water. Be careful not to allow water to enter the unit. Please be sure to always disconnect the power cord before cleaning. 4. Use only specified fuses. Do not use a substitute fuse which is of a different size and rating. Otherwise, damage may result to the unit. Do not substitute or modify any internal circuits. Exercise extreme caution when cables are over four feet in length. Turns off AC power (or disable unit) before disconnecting load or floating voltages. Operates the power supply with properly rated wire sizes. eID1.5 LOCATION AND COOLING 1. The proper operating temperature for the power supply are from 0 C to50C The unit ventilates by drawing air through the sides and exhausting it through the rear. 2. Proper ventilation area for the power supplies is at least 1 inch of spacing on all sides. 3. The PPS are built to configure into 1/2 rack mount configurations. 1.6 GPIB INTERFACE CONNECTOR The GPIB connector on the rear panel connects your supply to the computer and other GPIB devices. A GPIB system can be connected in any configuration (star, linear, or both)as long as the following rules are observed: 1) The total number of devices including the computer should not be greater than 15. 2) The total length of all cables used should not be more than 2 meters times the muimber of devices connected together, or a maximum length of 20 meters. Please do not stack more than three connector blocks together on any GPIB port. The resulting leverage can exert excessive force on the mounting panels. Make sure that all connectors are fully seated and that the lock screws are firmly hand tightened. Use a screwdriver only when removing the screw form the mounting panel.TWO: GETTING STARTED 2.1 UNIT FAMILIARIZATION Use the following illustrations of the power supplies in conjunction with the descriptions to familiarize yourself with the unit. Front Panel : Figure A, B - BK PRECISION | 1770 2 30.00V 0.000A , Figure A.Front Panel of Model 1770 -\ BK PRECISION" 1.002V 0.000A 0.000V 0.000A 5 Figure B.Front Panel of Models 1775/17802.1.1 FRONT PANEL KEYS <NOTES:> Most soft keys have two functions. The first function of the keys is function entry (i. e. VSET,ISET, OCP, etc.). The second function for the soft key is numeric data entry (i, e, 0-9). 1. LCD Display Displays alphanumeric information with status annunciators. A detailed listing of descriptions is presented in section LCD STAUS ANNUNCIATORS 2. Power On/Off Powers on the unit. 3. Negative Terminal Negative output terminal. 4. Ground Terminal Ground output terminal. 5. Positive Terminal Positive output terminal. 6. -S Terminal Negative remote sense (Applicable only for model 1770) 7. +8 Terminal Positive remote sense (Applicable only for model 1770) 8. VSET (7) Output control key used to display or alter the present voltage setting. Numeric entry key for number seven. 9. ISET (8) Output control key used to display or alter the present current setting. Numeric entry key for number eight. 10. TRK (9) Mode control key which activates the tracking mode on or off. (Applicable only for models 1775/1780). Numeric entry key for number nine. 11. LCL (CLEAR) Used in conjunction with the numeric entry keys to clear partially set commands and returns unit to the metering mode. Also returns the supply to Local mode when the unit is operating in the Remote mode. 12. OVSET (4) Output control key used to display or alter the overvoltage threshold. Numeric entry key for number four. 13. OCP (5) Mode control key which activates the OverCurrent Protection mode on or off. Numeric entry key for number five. 14. ADDR (6) System control key used to view or alter the GPIB address. Addresses available are 0-30. Numeric entry key for number six. 15. OUTPUT (ON/OFF) Mode control key which activates the output on or off. When the output is disabled, the LCD displays OUTPUT OFF . 16. OVP (1) Mode control key which activates the OverVoltage Protection mode on or off. Numeric entry key for number one. 17. A(2) This key increases the value of the digit to be varied. Numeric entry key for number 2.18. 19. 20, 21. 22. 23. BEEP (3) (0) () > CH (SELECT) UTILITY(ENTER) Activates the audible indicator on or off. Numeric entry key for number three. This key moves the cursor one digit left until it comes to the desired digit to be varied. Numeric entry key for 0. This key decreases the value of the digit to varied. Decimal point key. This key moves the cursor one digit right until it comes to the digit to be varied. This key allows you to select channel 1 or channel 2 (Applicable only for models 1775/1780). Reserved for future use. Enters the values in the setting mode and returns the display to metering mode.REAR PANEL: Figure E-1, E-2 ae Hf a Bo (< > CAUTION: { NO OPERATOR SERVICEABI Parts BIDE, REFER SERVICING TO. TRANED SERVICE PERSONNEL. oD) Carin FOR NING: PROTECTION AGAINST FIRE HAZARD, TYPE AND RATING OF PURE. GP-IB Cc) CO Co) Co Co) Co ices Gees 0 a of L fl To veux ZN eS op Ll lo g & SABOZIEIES BAROLIBIGS Figure E-1. Rear Panel of models 1775/1780 el fl Ch BA CAUTION: NO OPERATOR SERVICEABLE PARTS INSIDE. REFER SERVICING TO TRAINED @ SERVICE PERSONNEL WARNING: FOR CONTINUED PROT PROTECTION AGAINST Fi , Co) FES TYPE AND RATING OF FUSE. GP-IB ag BB RISTB3) Figure E-2. Rear Panel of model 17702.1.2 REAR PANEL 24, Ventilation ports - Exhausts warm air from the unit. 25. GPIB Interface - 24 pin parallel GPIB interface connector. 26. Voltage Selector - Selects voltage of either 11SVAC or 230(240)VAC, -10% ~ +10%, 50/60Hz. 27. Fuseholder - Fuseholder for AC line. 28, AC receptacle - AC plug for power cord. 29. Negative Terminal - Negative rear screw terminal output for hard wring. 30. Positive Terminal - Positive rear screw terminal output for hard wring. 31. -S - Negative rear screw terminal for remote sense output. Enables hard wiring. 32. +8 - Positive rear screw terminal for remote sense output. Enabled hard wiring. 33. Ground Terminal - Ground rear screw terminal. 34. External analog input voltage for programming output voltage. Input voltage ranges from 0 Volts to 10 Volts. 35. Voltage external programming reference point. 36. External analog input voltage for programming output current. Input voltage ranges from 0 Volts to 10 Volts. 37. Current external programming reference point. <NOTES:> 1. The rear panel configuration is identical on all power supplies. However, models 1775/1780 have an additional terminal strip for hard wiring the second channel. 2.2 LCD STATUS ANNUNCIATORS LIQUID CRYSTAL DISPLAY: Figure F-1, F-2, te|s 30.00V 0.000A &|oc2 iT)" INPUT ERROR! /%! ase Figure F -1. LCD of models 1775/1780__ {30.00V 0.000A *|~ ome High *) _ f Figure F-2. LCD of model 1770 The LCD display real time output Voltage/Current & mode status. There are no status indicators for CV mode. These messages are viewed in either local or remote mode. <NOTE:> 1. CCl - 2. CC2 - 3 RMT - 4. TRK - 5. OCP1 - 6. OCP2 - 7 OVP! - 8 OVP2 - 9. INPUT ERROR! 10. Highor Low Channel 1 is operating under constant constant current mode. When the indicator is off the supply is operating in constant voltage mode. Channel 2 is operating under constant current mode. When the indicator is off the supply is operating in constant voltage mode.(Applicable only for models 1775/17 80) The supply is operating in remote mode. The supply is operating in tracking mode. (Applicable only for models 1775/17 80) Overcurrent protection on channel 1 is enabled. When blinking, the overcurrent circuit has been activated and disabled the output. Overcurrent protection on channel 2 is enabled. When blinking, the overcurrent circuit has been activated and disabled the output. (Applicable only for models 1775/1780) Overcurrent protection on channel 1 is enabled. When blinking, the overcurrent circuit has been activated and disabled the output. Overcurrent protection on channel 2 is enabled. When blinking, the overcurrent circuit has been activated and disabled the output. (Applicable only for models 1775/1780) The numeric value entered is out of range. (Applies to all models) The supply is operating in either the high or low range. (Applicable only to model 1770) 2.3. OUTPUT TERMINALS AND WIRES All models have terminal blocks on the rear panel which include positive and negative outputs, positive and negative remote sense outputs, and earth ground.<NOTE:> The power supply is set at the factory local sense operation (i.e. the +S and -S terminals are strapped to the + and - terminals by a shorting plate at the rear terminal block). When operating in remote sense mode, remove the shorting plate and refer to section 3.3 for remote sense operation. Additionally, all models have positive, negative and earth ground terminals in the front of the unit. Remote sense capability is discussed detail in section 3.3. A brief definition of remote sense is a measurement of voltage at the load rather than at the output terminals. When local connections are made to the + and - terminals of the power supply, Wrap and bundle wires to reduce coupling effect. In order to safely and sufficiently handle electric current, the proper wire size must be selected. Select a wire size with sufficient rating to carry the current without overheating. Other factors to be taken into consideration are voltage drop and conductor temperature. The following table lists current carrying capacity of various wire sizes. For further information please refer to the NEC 1987 Handbook. TABLE 1: Stranded Copper wire Ampacity and Resistivity. Ampacity Per Wire (Amps) Wire Size 2 Wire Bundle 4 Wire Bundle Resistivity (AWG) (Amps) (Amps) (Ohm/ft) 20 7.8 6.9 0.0102 18 14.5 12.8 0.0064 16 18.2 16.1 0.0040 14 29.3 25.9 0.0025 12 37.6 33.2 0.0016THREE: OPERATING CHARACTERISITCS AND CONFIGURATIONS 3.1 INTRODUCTION These sections contain information on operating characteristics and how to configure a Power Supply. Sections 3.2 through 3.4 consider the power supplies operating ranges, remote sense operation and considerations when connecting loads. The latter half of the chapter deals with connecting power supplies in parallel and series configuration for CC and CV operation. 3.2 OPERATING RANGES All power supplies operate in either constant voltage (CV) or constant current (CC) mode over the rated output . Their respective voltage and current operating locus ( figure F ) are found in operating quadrants for all models. The power supply acts as a constant voltage source for comparatively large values of load resistance and as a current source for comparatively small values of load resistance, The automatic crossover or transition between these two modes of operations occurs at a critical stage or crossover value of load resistance; Ro = E,/Ig, where Eg is the front panel voltage setting and I, the front panel current setting. The followings are the operating quadrants (current -vs- voltage) of the power supplies. N IN Vmax V1 (igh) V2 (Low) NI \ I Imax 7 igh) 12 (Low) 7 Models 1775/1780 Model 1770 Figure G. Operating Quadrants 103.3 REMOTE SENSE When the supply is locally strapped for local sensing (normal operation), an unavoidable voltage drop is incurred in the load leads and this adds to its voltage regulation. By connecting the supply for voltage remote sensing, as shown in figure G, voltage is sensed at the load rather than at the output terminals. This allows the supply to automatically compensate for voltage drop in the load leads and improve regulation. In remote sensing, the VOUT? query and the front panel meter monitor load voltage at the sensing points. When the supply is connected for remote sensing, the OVP circuit senses at the main output terminal and not at the sense points. The voltage sensed by the OVP circuit could be significantly higher than the voltage bring regulated at the load. Therefore, set OVP threshold voltage accordingly. 3.3.1 REMOTE SENSE CONFIGURATION Turn off the power supply before modifying any connections on the rear panel terminal block. Configure the unit for remote sensing by first disconnecting the shorting plugs between the sense and load terminals. Connect the load and sense leads to the load as in figure G. Bear in mind that sense and load leads should be as short as possible. Additionally, the sense leads resistance should be no greater than 0.5 ohm/lead, and the voltage drop over the load leads should be no greater than 0.5V/lead. CAUTION: 1@y5 NO OPERATOR SERVICEABLE PARTS: INSIDE. REFER SERVICING TO TRAINED ) SERVICE PERSONNEL WARNING: FOR CONTINUED PROTECTION IN FIRE HAZARD, oF a g GP-IB c ay, ) Slelelelelels) + LOAD Figure G. Remote Sense Configuration 3.3.2 REMOTE SENSE CHARACTERISTICS OUTPUT NOISE: Any noise picked up on the sense leads will appear at the supply's output and may adversely affect CV load regulation. Twist the sense leads to minimize external noise pickup and run then parallel and close to the load leads. In noisy environments, it may be necessary to shield the sense leads. Ground the shield at the power supply end only. Do not use the shield as one of the sensing conductors. llSTABILITY: When the supply is connected for remote sensing, it is possible for the impedance of the load wires and the capacitance of the load to form a filter, which will become part of the supply's CV feedback loop. The extra phase shift created by this filter can degrade the supply's stability and can result in poor transient response performance. In extreme cases, it can cause oscillation. It is difficult to state simple rules defining the conditions under which this can occur, and which corrective action to take. A certain amount of trial and error may be called for. Two guidelines which are almost always valid are: a. Keep the leads short as possible. b. Twist the load leads together to minimize inductance. In most circumstances, once these two guidelines are followed, problems associated with the load lead inductance are eliminated. This leaves the load lead resistance and load capacitance as the major cause of the reduced stability. In this case, you may obtain further improvement to the stability by: a. Keeping the load capacitance as small as possible. b. Increasing the diameter of the load lead to reduce resistance. If heavier gauge load lead (# 10 or greater) are used, circumstances may arise when the load lead inductance and the load capacitance can form an underdamped filter. This filter occasionally has the effect of destabilizing phase response. In this case, the above steps can worsen stability since they will reduce damping in the system. 3.4 LOAD CONSIDERATION AND MULTIPLE LOADS CONNECTION When the supply is in local sensing mode and you are connecting multiple loads to the output, connect each load to the output terminal using separate load leads. This minimizes mutual coupling effects and takes full advantages of the supply's low output resistance. Each pair of wires should be as short as possible and twisted or bundled to reduce lead inductance and noise pickup. If cabling considerations require the use of distribution terminals that are located remotely from the supply, connect the power supply output terminals to the remote distribution terminals by a pair of twisted or bundled wires. Connect each load to the distribution terminals separately. Remote voltage sensing is recommended in these circumstances. Sense either at the remote distribution terminals or, if one load is more sensitive than the others, directly at the critical load. OUTPUT ISOLATION: The output of the power supply is isolated form earth ground. Hither output terminal may be grounded, or an external source of voltage may be connected between either output and ground. However, both output terminals must be kept within +/-240Vdc of ground. This includes the output voltage. An earth ground terminal is provided on the rear panel terminal block. Each of the power supplies will operate accordingly to the various types of loads connected to the output . CAPACITANCE LOADING: In normal conditions, the supply will be stable for almost any size load capacitance (for remote sense stability considerations). However, large load capacitance may cause ringing in the supply's transient response. It is even possible that certain combinations of capacitance and ESR (equivalent series resistance) will result in instability. If this is the case, the solution is to increase or decrease total load capacitance. In addition, the overvoltage protection SCR crowbar circuit has been designed to discharge capacitance up to a certain limit. These limits are: 1. For models of which maximum output voltage is below 18 Volts, Capacitance should not exceed 5000uF. 12For models of which maximum output voltage is below 35 Volts, Capacitance should not exceed 5000uF. For models of which maximum output voltage is below 60 Volts, Capacitance should not exceed 3000uF. For models of which maximum output voltage is below 128 Volts, Capacitance should not exceed 470uF. For models of which maximum output voltage is below 250 Volts, Capacitance should not exceed 220uF. <NOTE: > If load capacitance approaches these limits, it is recommended to not intentionally activate the OVP circuit and discharge the capacitance through the SCR crowbar as part of standard testing procedure. wR wN 3.5 PARALLEL CONNECTION OPERATION <NOTE:> Power supplies equipped with SCR crowbars should not be used in series or parallel with each other unless a master-slave interconnection is employed and their crowbars interlock . Greater current capability can be achieved by connecting output in parallel. However, only power supplies which have equivalent voltage and current output ratings may be connected in parallel. Otherwise, damage to the unit may result. A typical connection is shown in figure H through the back of models 1775/1780 in local sensing. All leads are kept as short as possible and are bundled together. Second, connect remote sense terminals to compensate for the voltage drop in the interconnecting load leads. Lastly, the CV and CC operations have identical setups. CAUTION: Ss NO OPERATOR SERVICEABLE PARTS INSIDE, REFER SERVICING TO TRAINED SERVICE PERSONNEL. Co) Co WARNIN FOR RING: PROTECTION AGAINST FIRE HAZARI TYPE AND RATING OF FUSE. ) GP-IB ) WwW 5) SERRE GREE + LOAD Figure H. Parallel Configuration 133.5.1 CV OPERATION Although both outputs operate independently of each other in CV operation, one of the outputs must dominate (control) over the other. Additionally, the dominant output must operate in CV mode, while the other output may operate in CC mode. As an example of this operation, lets assume in figure H. that output channel two operates in CC mode and output channel one operates in CV mode. Perform the following steps: 1. Set output channel two to the maximum output voltage of desired range. 2. Set output channel one to the desired operating voltage. The voltage of output channel one controls the voltage across the load. The output currents are algebraic sums of the individual outputs. 3.5.2 CC OPERATION The CC operation is similar in many ways to the CV operation, except that the output current must also be set. To obtain CC operation, perform the following steps: 1. Program output voltage of the two channels to the desired operating voltage. 2. Program output channel one to one-half the desired operating current. 3. Program output channel two to one -half the desired operating current. Both output operate in CC mode. 3.5.3 REMOTE SENSING CONFIGURATION (Parallel Connection Mode) The following figure I illustrated the configuration for Remote Sensing in Parallel Operation. CAUTION: @ Nae aoe ear Ie TRAINED @ @e SERVICE SaSone. eo TC warns FOR CONTINUED, PROT PROTECTION ST PRE AGAIN: ED TYPE AND RATING OF POSE. GP-IB Pekka & & @ oar chav 2 | alo ve wax ZN ont Bees LH l fr } Neal | Yared + LOAD | _____}-+ Figure I. Remote Sense, Parallel Mode 143.6 SERIES CONNECTION OPERATION <NOTE:> Power supplies equipped with SCR crowbars should not be used in series or parallel with each other unless a master-slave interconnection is employed and their crowbars interlock. Greater output voltage capability can be obtained by connecting output in series. A note of caution, since current the same in each element of a series circuit, both output need identical rated currents. If this is not followed excessive current may be forced into one of the output and cause a failure. > Figure J illustrates the Series configuration on Models 1775/1780. >) CAUTION: | @ | NO OPERATOR SERVICEABLE PARTS INSIDE. REFER SERVICING TO TRAINED @ @ SERVICE PERSONNEL. ( ) ( ) WARNING: AGAINST FIRE. D, oT Co ORES TYPE AND RATING OF FUSE. GP~IB Seeeeies Seeds @| |} E @ OUTPUT CHRNNEL ! 240 Ve MAX ZN OUTPUT CHANNEL odo Yo" MAX @ + LOAD Figure J. Series Configuration 3.6.1 CV OPERATION In CV operation, first program the current of both output to the desired value. Secondly, program the desired operating voltage to equal the sum of the output voltages. 3.6.2 CC OPERATION In CC operation, one output will operate in CV mode, the other in CC mode. To obtain this operation, perform the following: 1. Program the output current of the two channels to the desired operating current. 2. Program output channel one to one-half the desired operating voltage. 3, Program output channel two to one-half the desired operating voltage. At load levels less then one half the total voltage limit, the output that was originally in CC mode, stays in CC mode. At load voltages greater than one-half the total voltage limit, the output that was originally in CC mode, changes to CV mode. The secondary output will regulate the current in CC mode and provide the necessary voltage. 15REMOTE SENSE CONFIGURATION (Series Connection Mode) The following figure K illustrates the configuration for Remote Sensing in Series Operation. S 1 CAUTION: @ { NO OPERATOR SERVICEABLE PARTS ieee ease [fl Cc > C ) WARNING: FOR CONTINUED PROTECTION c CoB: HAZARD, REPLACE ONLY WITH SAME TYPE AND RATING OF FUSE. GP-IB CISSISIES aeekeeee ) a channel. 2 ~ a ve wx ZN e ape 240 eg ey LOAD Figure K. Series Configuration with Remote Sense 16FOUR: LOCAL OPERATION 4.1 INTRODUCTION These sections contain information on how to locally program the PPS Series. Upon power up, the power supplies default to local mode operation. All front panel keys may be used to control the power supply. <NOTES:> The PPS series power supply models and their operations are essentially identical. However, two of the supplies provide more functions (i.e. models 1775/1780 have dual output and model 1770 has two output operating ranges) which may slightly alter or add to programming procedures. Therefore, please refer to the appropriate sections for these operation. All operations performed in local mode, may also be performed in remote mode. The unit indicates remote operation when the " RMT" annunciation on the display is on. 4.2 GENERAL INFORMATION 1. The power supplies are able to directly accept programming values of voltage, current and overvoltage. "When a valid input is made, the unit will round off the value to the nearest multiple of the resolution". If a nonvalid input is made, the unit will display "INPUT ERROR! " and return to previous set values. 2. The actual operation of programming the voltage and current values is simple. Simply, press any of the functional keys and the display shows the present value. To change this value, simply use the numeric keys to enter a value. If an error is made, press the " CLEAR" key and then reselect the parameter that was to be modified. Once the final value is set, press the " ENTER" key. LCD module will display the actual value, initiate the function, and return the unit to metering mode. If a user wishes to recall a setting, press the function key pertaining to the operation. For example, to recall a set voltage, press " VSET" and then press "ENTER"or "CLEAR" key to return unit to metering mode. 3. To reset any of the output parameters (i.e. VSET, ISET, OVSET) simply press the desired function key, enter the new value and press "ENTER". The Programming steps are identical to steps are identical to steps described in sections 4.3-4.5, 4. Models 1775/1780 have two output (channels) and these may be alternately viewed via the CH/SELECT key. In order to program the output parameters for each output channel, first toggle the *CH/SELECT* key to the desired channel and then observe the following guidelines. 4.3 SETTING VOLTAGE To locally program the voltage (VSET), press "VSET", enter the value and press ENTER! For example, if one wished to set a voltage of 3.99, press: VSET UTILITY 7 3 9 9 ENTER the LCD display 3.99 and the unit returns to metering mode. 17AVSET description: For all models, VSET can be altered by pressing A* or W* key instead of VSET* and entry keys. When the power supply is in the CV mode, pressing &* key will increase output voltage per step. The increment step is determined by either pressing the * or '}* key until the cursor comes to the digit to be varied. The LCD module would show the following: cursor The operation of W* key is similar to A* key for decreasing the output when power supply is in CV mode. 4.4 SETTING CURRENT To locally program the current (ISET), press "ISET" and enter the value and then press"ENTER. For example, if one wishes to set a current of 1.69 amps, press: ISET UTILITY 8 1 . 6 9 ENTER the LCD displays 1.69 and the unit returns to metering mode. For all models, ISET can be altered by pressing "A" or W* key instead of ISET* and entry keys. When the power supply is in the CC mode, pressing "A* key will increase output current per step. The increment step is determined by either pressing * or * key until the cursor comes to the digit to be varied. The LCD module would show the following: cursor The operation of W key is similar to A* key for decreasing the output when power supply is in CC mode. 184,5 SETTING THE PROTECTION MODES The power supplies have overvoltage protection (OVP) and overcurrent protection (OCP) features to guard against abnormal operating conditions. When either of these two functions are activated, the unit disables the output. The LCD annunciation will indicate the condition and an audible signal will sound. 4.5.1 SETTING THE OVERVOLTAGE THRESHOLD To locally program the threshold voltage press "OVSET", enter the value and press "ENTER". For example, to program an overvoltage value of 4.50V, press: OVSET UTILITY 4 4 . 5 0 ENTER 4.5.2 ENABLING / DISABLING OVERVOLTAGE PROTECTION In all models, the user can enable or disable the OVP circuit by pressing the "OVP/4" key. When enable the OVP annunciation is on. When the OVP annunciation is blinking, the overvoltage protection circuit has been activated and disabled the output. An audible signal will also sound. To reset, Press the "OVP/4" key and the annunciation will stop blinking. Turn the output on and press the "OVP/4" key again. <NOTES:> When remote sensing, take into consideration the voltage drop across the load leads since the threshold measurement is taken at the output terminals. In inductive load applications, a high-surge voltage would enable the OVP circuit and disable the output. Also note the programming resolution and programming accuracy specifications. When the OVP circuit is disabled, the threshold voltage becomes invalid. 4.5.3 ENABLING / DISABLING OVERCURRENT PROTECTION To enable the overcurrent protection circuit, press the "OCP/S" key and the OCP annunciation is tumed on. To disable the overcurrent protection, press the "OCP/S" key again and the annunciation is turned off. When the OCP annunciation is blinking, the overcurrent protection circuit has been activated and disabled the output. An audible signal will also sound. To reset, Press the "OCP/S" key and the annunciation will stop blinking. Turn the output on and press the "OCP/S" key again. <NOTE:> If OCP is on and the constant current mode (CC) is activated, the power supply output is disabled. 194.6 ENABLING / DISABLING OUTPUTS All modes have the capability of disabling their output to have their setting parameters modified. Once the modification has been completed, one can enable the power supply to operate at the new values. The output is enabled or disabled by pressing the "OUTPUT (ON/OFF)' key. Models 1775/1780 output is enabled or disabled by selecting the channel/s and pressing the "OUTPUT (ON/OFF)" key. 4.7 TRACKING OPERATION (Models 1775/1780) Models 1775/1780 have the ability of tracking since it has two outputs. When the tracking mode is enabled, the annunciation is on. The output of channel two is identical (in sync. with) to channel one and is controlled by channel one. For instance, a voltage increase in channel one would also cause a voltage increase in channel two. 4.8 RANGE OPERATION (Model 1770) Model 1770 has two operating ranges, "High" or "Low". These ranges are controlled by adjusting the voltage and current values to the appropriate programming settings (refer to fig. G section three & appendix A). The LCD displays "Low" when the low range is active or "High", when the high range is active. For more information on operating range characteristics, please refer to section 3.2. 4.9 AUDIBLE SIGNAL The power supplies have an audible indicator, which allow monitoring of operating conditions. When functions are activated or parameters set, the audible signal will sound. Should the protection modes be activated an audible signal will sound, indicating a change in an operating mode has occurred. The LCD and annunciators will indicate the condition. This feature can also be disable or enabled by pressing the "BEEP" key. 20FIVE: REMOTE OPERATION The programmable Power Supply Series from B+K Precision compatible with ANSI/TEEE 488.1. This is the "Standard Digital Interface for Programmable Instrumentation". This standard provides a means for an electrical mechanical system to interconnect measurement devices. Several key specifications of IEEE 488.1 are: Interconnect Devices - Up to 15 devices on one bus. e Interconnection Path - The total transmission path for a star or linear bused networks is up to 20 meters. Signal Lines - Sixteen active lines; 8 data lines, and 8 interface and communication management lines. Message Transfer Scheme - Byte-serial, bit-parallel, asynchronous data transfer using interlocking three wire handshake technique. Maximum Data Rate - One megabyte per second over limited distances. Typical transmission rate is 250 kilobytes per second. The actual data transmission rate is usually determined by the slowest device in communication at that time. e Address Capability - There can be a maximum of one talker and up to 14 listeners at one time. e Pass Control - If a system has more than one controller, only one controller may be active at atime. The active controller may pass control to one of the other passive controllers. Only the controller designated as system controller can demand control. However, a non-active controller may request control. Interface Circuits - Driver circuits are TTL and Schottky compatible. 5.1 INTRODUCTION This section contains information on controlling the power supply via a computer. This material is presented in a normal manner in which a majority of programmers may benefit. Main topics of operation to be covered are: GPIB Operation Programming Syntax Programming the Power Supply The GPIB sections discuss the interface functions, settings and interface. The Programming Syntax section lists all available programming commands. Last, "Programming the Power Supply" includes a variety of conditions, commands and.samples useful for controlling the power supply via the computer. 215.2 GPIB OPERATION The GPIB (General Purpose Interface Bus ) operation allows for constant talk and listen between systems. The PPS series are able to act as both talkers and listeners. The computer is able to act as a talker, listener, and controller. LISTENER: A device capable of accepting data over an interface. TALKER: A device capable of transmitting data over an interface. CONTROLLER: A device capable of specifying the talker and listener for an information transfer. 5.2.1 GPIB INTERFACE FUNCTIONS: Even though the GPIB control is implemented in the power supply, instructions are only enabled when a computer is equipped with a GPIB interface controller card. A controller manages the operation of the bus system by designating which devices to send and receive data. The controller also provides command specifications within other devices. The PPS series supply the following IEEE-488 interface functions: L4 - Basic Listener, Unaddressable if MTA T6 - Basic Talker, Serial Poll, Unaddressed if MTA SH1 - Full Source Handshake AHI - Full Acceptor Handshake RL1 - Remote & Local Lockout DC1 - Device Clear El - Open Collector Driver Electronics (250kb/s max) CO - Non-system controller SRO - Omitted Service Request Function TEO - Omitted extended talker function LEO - Omitted extended listener function PPO ~ Omitted parallel poll function DTO - Omitted device trigger 5.2.2 ADDRESS SETTING OF GPIB INTERFACE The main purpose of address setting is for specifying unit identification between the instruments and controller in a GPIB connection system. The PPS Series has 31 addresses (0-30) available. If a number higher than 30 is selected, the display shows " INPUT ERROR" and defaults to previous values. The power supplies are preset at the address 12 by the factory. To view the present address, press the "ADDRESS" key. If the present value is incorrect, enter in a new value with numeric keys and press "ENTER" key. In remote mode, the "ADDRESS" command is available to modify the address. 22a" 5.3 PROGRAMMING SYNTAX The following table lists programming commands available with the PPS Series. These standard GPIB commands readily interface with programming languages. Note that this portion of the manual only deals with GPIB commands. No programming language commands are presented here. Appendix A gives a summary of the command definitions. 5.3.1 GPIB DEVICE COMMANDS LIST Command Model 1770 Models 1775/1780 Type Input / Output CALCHNL [0,1] [0,3] I Input OcP {0,1] [0,1] I Input OUT [0,1] - I Input OUT1 f0,1] ] Input OUT2 [0,1] I Input TRACK [0,1] I Input OVP f0,1] [0,1] I . Input PROGRAMMING COMMANDS VSET * R Input {SET * R Input OVSET * R Input VSET1 * R Input VSET2 * R Input ISET1 * R Input ISET2 _* R Input OVSET1 * R Input OVSET2 * R Input ADDRESS * * I Input QUERY COMMANDS VOUT? * R Output IOUT? * R Output VSET? * R Output ISET? * R Output OVSET? * R Output VOUT1? * R Output VOUT2? * R Output IOUT1? * R Output IOUT2? * R Output VSET1? * I Output VSET2? * R Output ISET1? * R Output ISET2? * R Output OVSET1? * R Output OVSET2? * R Output STATUS? * * A Output ERROR? * * A Output 235.3.2 CALIBRATION COMMANDS Command Model 1770 Models 1775/1780 Type Input/Output VOFF * * R Input VFS * * R Input IOFF * * R Input TFS * R Input NOTE: 1. Types ofdataentry: 1: Integer R: Real A: ASCII code 2. Types of input/output: INPUT: Input to the PPS OUTPUT: Output to the PPS 3. The" CALCHNL" commands for Models 1775/1780 are: 0 -disable calibration, 1-calibrate channel one, 2-calibrate channel two, 3-calibrate both channels. 4. * => Command available to the model. 5.4 STATUS REPORTING All models include a status register for reporting the operating conditions of the power supply. Each output channel has an 8 bit register which signifies a true condition as "1" and a false condition as "0". There bit conditions stay true as long as the condition is true. The status word received is in ASCII code format, and needs to be converted to binary code. Each bit is assigned a particular condition and one nibble is converted to one ASCII code. The single channel PPS send two ASCII Bytes and two Terminator Bytes to the GPIB. The terminator bytes are " line feed" & "carriage return". The deal channel PPS send four bytes of ASCII and two terminator bytes to the GPIB. STATUS? DEFINITION OF STATUS WORD: NIBBLE 1 NIBBLE 1 Byte value bit 7 b6 bS b4 b3 b2 bl b0 0 BEEPOFF HIGHRNG CV MODE 0 0 OCP OFF OUT ON No Error 0 1 BREPOFF LOWRNG CCMODE ov oc OCP ON OUT OFF Error 0 0 0 CV2 MODE 0 0 OCP OFF OUT ON CHI ] 1 0 TRACK CC2 MODE ov2 oc2 OcP ON OUT OFF CH2 NIBBLE 3 NIBBLE 4 <NOTE:> Byte 0 is available for all PPS models. However, byte 1 is only applicable for the dual channel models. 24An explanation of these bytes/bits is as follows: bit 7 (Byte 0) - Audible indictor is off (0) or on (1). b6 (Byte 0) - Signifies the high range (0) or low range (1). Applicable to Model 1770. b6 (Byte 1) - Signifies whether or not Models 1775/1780 are in tracking mode. b5 - Signifies which mode the power supply is operating in, constant current constant voltage. b4 - Overvoltage has toggled on (1). b3 - Overcurrent has toggled on (1). b2 - Overcurrent protection mode is on or off. b1 - The output is on or off, bO - error has occurred. b0O (Byte 1)- CH1 or CH2 is selected (cursor). we eOnnu Fs WY > So Example: Reading the Status (dual channel) After the "STATUS? " command is entered is entered, the following ASCII code will be read from the PPS: ASCH CODE 30 31 31 35 36 convert to decimal form DECIMAL CODE 0 1 1 5 6 convert to hex form HEX CODE 0484 convert to binary form Byte 1 Byte 0 Nibble 3 Nibble 4 Nibble 1 Nibble 2 BINARY CODE 0000 0100 1000 0100 EXPLANATION OF STATUS BITS: BYTE 0b7 = BEEP on, b5 = CH1 in CV mode, b2 = CH1 OCP on, b1 -CH1 OUTPUT on. BYTE 1b5 = CH2 in CV mode, b2 = CH2 OCP on, b1 = CH2 OUTPUT on, b0 = Cursor at CH1. 5.5 PROGRAMMING THE POWER SUPPLY This section provides more detailed requirements of the programming commands available. Upon powering up, the PPS Series undergo self test and default to the factory settings. INITIAL DEFAULT SETTINGS OF PPS: COMMAND Model 1770 Models 1775/1780 OUT 1 - OUTI - 1 OUT2 - 1 VSET 0/0 - ISET 0.0140/0.0140 - OVSET maximum - VSET1 - 0 25VSET2 - 0 ISET1 - 0.0140 ISET2 - 0.0140 OVSET1 - maximum OVEST2 - maximum ADDRESS 12 12 5.5.1 OUTPUT ON/OFF All power supplies have their outputs off upon powering up. The command "OUT" is to enable/disable the outputs. To enable the power supply, designate the channel (Models 1775/1780 only) and condition (1=on; 0=off). For example to disable an output, Enter: OUTO To view if an output is on or off, query the status of the power supply. 5.5.2 VOLTAGE PROGRAMMING To program a voltage, specify an output channel (Models 1775/1780 only) and voltage. <NOTE:> The default output condition of a power supply is" OFF " at startup. All values of voltage must be in volts (i.e. no millivolts). This operation hold true for voltage settings in CV mode. Thus, actual voltage is the programmed voltage and the programmed current is the current limit. In addition, the specified voltage value will be rounded off to the nearest multiple of resolution. For example, to program a channel for 16 volts. Enter: VSET 16 To readback the programmed value, send the query: VEST? and address the power supply to talk. To read back the voltage output of the channel, send the query: VOUT? Once again, the power supply should be addressed to talk and the results displayed (.e. shown on CRT, printed, or saved). Models 1775/1780 have two outputs, please refer to the programming syntax commands for proper nomenclature of commands. 5.5.3 OVERVOLTAGE PROGRAMMING (OVSET) In order to protect loads against excessive voltages, an overvoltage protection circuit (SCR crowbar) has been added. When a voltage exceeds the set overvoltage value the power supply output is disabled. 26To program overvoltage, specify the output channel (Models 1775/1780 only) and overvoltage value. For example. to program one channel of the Model 1775 for 18V, Enter: OVSETI 18 To readback the programmed value for channel one, send the query: OVSET1? and address the power supply to talk. When specifying the queries, only one command may be issued at a time. The power supply can access only one query at a time. 5.5.4 CURRENT PROGRAMMING To program a current, specify an output channel (Models 1775/1780) and current. All values of current must be in amps. Additionally, the unit rounds off ISET to the nearest multiple of resolution. For example, to specify a current of 1.6 amps. Enter: ISET 1.6 This operation holds true for current settings in CC mode. When the supply operates in CC mode, the actual current is the programmed current and programmed voltage is the voltage limit. To readback the programmed value, send the query: ISET? and address the power supply to talk. To readback the current output of the channel, send the query: IOUT? Once again, the power supply should be addressed to talk and the results displayed (i.e. shown on CRT, printed, or saved). Models 1775/1780 series have two outputs, please refer to the programming syntax commands for proper nomenclature of commands. 5.5.5 OVERCURRENT PROTECTION (OCP) The overcurrent programming feature protects the load from excessive output currents. The OCP mode cannot be used while the power supply is operating in CC mode, since OCP would disable the output. The OCP command is enabled by a logic " 1" and disabled by a logic " 0". For example, to enable a channel for overcurrent protection. Enter: OCP1 to disable a channel form OCP, Enter: OCPO 275.5.6 TRACK COMMAND This command may be controlled by a true "1" or false "0" command. The "TRACK" command is only applicable to Models 1775/1780. The ensuing example will assist in clarifying the command. To set the tracking mode in Models 1775/1780, send " TRACK 1" Refer to section 4.7 for more information on Models 1775/1780 tracking mode. 5.6 FUNDAMENTALS OF PROGRAMMING The following section explains fundamental operations of programming the supply in remote mode. Before beginning operation, have your system completely installed and set up accepted, do not have a load applied at the outputs. Be aware at all times of power supply ' s voltage and current limits. If data greater than the range of the power supply is programmed, data is disregarded and a error occurs. Due to the extent of programming languages available, only common programming commands will be discussed. ADDRESS SELECTION: The first step involved in remote programming is to select the power supply's address. The present power supply address may be viewed via the front panel address key or in the Default Conditions List. To alter this address, press the address key, select a new address (0-30) and press " ENTER" key. The data is stored in an EEPROM. COMMON COMMANDS: There is a wide variety of commands available to program the power supply. However. the commands which pertain to voltage and current are of most use. These commands are: VSET, ISET, OVSET, VOUT?, IOUT?, OVSET? and COP. Secondary commands of prime importance pertain to the actual programming language. Some of these commands are: OUTPUT, ENTER, DELAY, SEND, PRINT, and CLEAR. The definitions and uses of these commands are as follows: OUTPUT: Addresses the power supply to listen and sends command to power supply. ENTER: Addresses the power supply to talk and receive data from the power supply. DELAY: Introduces a time delay to the power supply. <NOTE:> This command is extremely important since the power supplies occasionally require time delays in order to execute operations. Otherwise, error messages occur. CLEAR: Clears the power supply. <NOTE:> The PPS series does not have a CLR command. Therefore, the user must initially specify a hardware clear before beginning programming, , SEND: Sends GPIB management commands. PRINT: Writes data to the screen or to a file. 28All commands may be accepted in either upper or lower case letters in ASCII code. The PPS series accepts integer or numeric data as input. Plus (+) and minus (-) signs are also numeric characters. Remember not to program too large a value since the power supply rounds off data to suit the power supplies resolution. SENDING DATA: The steps involved in sending data to the power supply are setting the address (power supply & computer), function and sending the command (Qbasic). For example, to turn on the output of a power supply (single output), send: PRINT #1, "OUTPUT 12; out 1" where: PRINT Qbasic command. Writes data to the screen or to a file #1 File number OUTPUT Qbasic command . Specifies that the file is opened for sequential output 12 GPIB device address OUT GPIB command 1 Enable output (0 disables output) Continuing on with this example we will set the output voltage to 11V and output current to 1.7 amps, therefore send: PRINT #1, "OUTPUT 12; out 11" PRINT #1, "OUTPUT 12; out 1.7" <NOTE:> The voltage and current values are given in volts and amps. OBTAINING DATA: The steps involved in obtaining data from the power supply follow a similar formats as in sending data. However, additional commands (Enter and Print) are necessary to view the data. For example, to query the programmed voltage of the previous example, send: PRINT #1, "OUTPUT 12; VSET?" Although a query has been sent to the power supply, there has been no command given to view the data. At this moment the power supply holds the VSET value in a sample/hold circuit till the proper command has been executed. Therefore, to retrieve data onto the screen, send: PRINT #1, "ENTER12" INPUT #2, VOLTAGES PRINT " VOLTAGE SETTING =" ; VOLTAGE$ The PPS series are capable of output voltage and current to the bus. Therefore, one may send queries to read in the values from the supply. In our example we set an output voltage of 11V and current of 1.7A. Let us recall these actual output values. To query the voltage output of the power supply, send: PRINT #1, "OUTPUT 12; VOUT?" Now, proceed to obtain the voltage output value: PRINT #1, "ENTER 12" INPUT #2, V$ PRINT "VOUTPUT =" ;V$ The screen now shows a value of approximately 11V. 29To query the current of the power supply, send: PRINT #1, "OUTPUT 12; 1OUT?" Now, proceed to obtain the current output value: PRINT #1, "ENTER 12" INPUT #2, I$ PRINT "IOUTPUT =" :I$ Now, simply short the output terminals, and the LCD screen will now display a value of approximately 1.7 amps. The same methods presented here hold true for programming overvoltage and overcurrent protection as well as other GPIB commands. In order to return the supply to local mode, press the " LCL key on the front panel. <NOTE:> Attempting to modify values/conditions via the front panel display during remote operation is not possible. However, values/conditions may be monitored operation. 30SIX: CALIBRATION 6.1 INTRODUCTION This addendum describes calibration procedures for the B+K Precision Programmable DC Power Supply. The supply is calibrated either through local or remote control. The following information provides calibration procedures in local mode. NO hardware adjustment is necessary since all calibration is accomplished by software. The software sends calibration constants to the supply via the front panel keys. Calibration should be performed at least annually. The four parameters that must be calibrated are output voltage, output current, readback voltage and readback current. After all the power supply parameters are calibrated, the supply returns to normal operating condition. If there are any errors in the calibration, cycle the power and recalibrate. All constants are saved in a non-volatile EEPROM. 6.2 CALIBRATION CONFIGURATION There are two configurations for calibration of power supplies. One of which would be for voltage and the second for current. The two pieces of equipment necessary for calibration are: 1. Precision Shunt Resistor -0.1 ohm/10 Amp, 0.001% accuracy (for smaller current) or 0.05% accuracy (for larger current), 20ppm, 10 watts. 2. DMM (DC voltage and current) -5 digit, 0.005% accuracy. DVM REAR OUTPUT TERMINAL _ + +$ + ~~ -$ 9 PDD PDH Figure M. Voltage Calibration Configuration 31DVM REAR OUTPUT TERMINAL + +$ + ~~ - ?9 D/P D/P PRECISION <| SHUNT RESISTOR Figure N. Current Calibration Configuration 6.3 LOCAL CALIBRATION The following steps describe the calibration procedure of the supply via front panel keypads in mode. CAUTION: In these procedures, voltages and currents may exceed full scale value. Take all necessary precautions. STEPS: L. Disconnect all loads from the supply. 2. Strap the supply for local sensing. 3. Connect the voltmeter to the +S and -S rear terminals as in figure M. for Voltage calibration. 4. Turn on the power supply and press " 8" &" ON/OFF" simultaneously. 5. The supply will begin the voltage and current calibration process. VOLTAGE CALIBRATION 1. The supply initially sends an offset voltage to the output. This offset voltage is measured on the DMM. 2. Enter the " V Lo=" value to the power supply by the front panel keys, and press "ENTER" once. For example, if the DMM reads 4.662 V, press: 4} Ls} tLe} [se } {2} [ENTER 3. After calibrating the voltage offset, the supply sends full scale voitage to the output. This value is measured on the DMM. 324, Enter in the " V Hi =" value to the power supply by the front panel keys and press" ENTER" once. For example, if the full scale is 14.369 V as measured by the DMM, press: La] C+) Le} L323] Le |} (| 2 J} LENTER The voltage calibration is now complete! CURRENT CALIBRATION: 1. When the voltage calibration is complete, connect the voltmeter to the Precision Shunt Resistor as in figure N. 2. The supply initially sends an offset current to the output. This offset current is measured on the DMM. 3. Enter the " I Lo = " value to the power supply by the front panel keys, and press " ENTER" once. For example, if the DMM reads 103 mV, press: 1 | Le J] te} 3 4f ENTER 4, After calibrating the current offset value, the supply sends full scale current to the output. This value is measured on the DMM. 5. Enter the " I Hi = " value to the power supply by the front panel keys, and press " ENTER" once. For example, if the DMM reads .3301 V press: C3) Ce) 3) [eft ttf. LENTER | 6. The current calibration is now complete! <NOTE:> For Models 1775/1780, Ch.1 and Ch.2 can only be calibrated in sequence (applies only in local mode). 6.4 REMOTE CALIBRATION The PPS series are able to be calibrated via computer commands. Therefore it is not necessary to remove the power supply from the system. There are several commands available for calibration. These are; CALCHNL, VOFF, VFS, IOFF, IFS. A definition of these commands is presented in appendix A. The equipment necessary for calibration is identical to the equipment used in local mode. Refer to figures M and N for voltage and current calibration configurations. 6.5 CALIBRATION PROGRAM EXAMPLE Please refer to Appendix D. 33SEVEN: USER MAINTENANCE/SERVICE 71 FUSE REPLACEMENT If the fuse is suspected to be defective, it should be inspected and, if necessary, replaced. To inspect or replace the fuse, please perform the following steps: (1) Disconnect the AC line cord from the unit to reduce electrical shock hazard. (2) Remove the fuse by sliding out the fuse holder. The fuseholder is beneath the AC Receptacle. Test the fuse for electrical continuity with an ohmmeter. (3) If the fuse us found to be defective, replace it with a replacement fuse as specified in the following table: Models Fuse Rating Model 1770 230V~/2AT, 250V 115V/4AT,250V Models 1775/1780 230V~/2AT, 250V 11I5V/4AT,250V (4) Replace the fuse in the fuseholder and re-install. (5) Reconnect the AC power cord. <NOTE:> USE OF ANY FUSE OTHER THAN THE ONE SPECIFIED MAY CAUSE DAMAGE TO THE UNIT, POSE A SEVERE FIRE HAZARD, AND WILL VOID THE WARRANTY. 7.2 IN CASE OF DIFFICULTIES This programmable power supply has been designed to be accurate, reliable, and easy-to -use. However, it is possible that you may experience difficulties during operation. If there appears to be any kind of problem during the use of the unit, please perform the following steps to help determine the cause: (1) Re-read the operating instructions. It is very easy to inadvertently make mistakes in operating procedure. (2) Remove and test the fuse. The power supply will not function with an open fuse. If the preceding two steps fail to resolve the problem, please call your local distributors. <NOTE:> ATTEMPTED REPAIR, MODIFICATIONS, OR TAMPERING BY UNAUTHORIZED PERSONNEL WILL VOID THE WARRANTY. 347,3 LIMITED THREE YEAR WARRANTY B+K Precision warrants to the original purchaser that its product and the component parts thereof, will be free from defects in workmanship and materials for a period of three years from the date of purchase. B+K Precision will, without charge, repair or replace, at its' option, defective product or component parts. Returned product must be accompanied by proof of the purchase date in the form a sales receipt. To obtain warranty coverage in the U.S.A., this product must be registered by completing and mailing the enclosed warranty card to B+K precision, 1031 Segovia Circle, Placentia, CA 92870 within fifteen (15) days from proof of purchase. Exclusions: This warranty does not apply in the event of misuse or abuse of the product or as a result of unauthorized alternations or repairs. it is void if the serial number is alternated, defaced or removed. B+K Precision shall not be liable for any consequential damages, including without limitation damages resulting from loss of use. Some states do not allow limitation of incidental or consequential damages, so the above limitation or exclusion may not apply to you. This warranty gives you specific rights and you may have other rights, which vary from state-to -state. Model Number: Date Purchased : 357.4 SERVICE INFORMATION Warranty Service: Please return the product in the original packaging with proof of purchase to the below address. Clearly state in writing the performance problem and return any leads, connectors and accessories that you are using with the device. Non-Warranty Service: Please return the product in the original packaging to the below address. Clearly state in writing the performance performance problem and return any leads, connectors and accessories that you are using with the device. Customers not on open account must include payment in the form of a money order or credit card. For the most current repair charges contact the factory before shipping the product. Return all merchandise to B+K Precision with per-paid shipping. The flat-rate repair charge includes return shipping to locations in North America. For overnight shipments and non-North America shipping fees contact B+K Precision. B+K Precision 1031 Segovia Circle Placentia, CA 92870 Phone: 714-237-9220 Facsimile: 714-237-9214 Include with the instrument your complete return shipping address, contact name, phone number and description of problem. 36APPENDIX A: SPECIFICATIONS The following lists the performance specifications for the B+K Precision. Linear Programmable DC Power Supply Series. All specifications are at rear terminals with a resistive load, and local sensing unless otherwise stated. All specifications apply over the full operating temperature range of 0 C to 50 C unless otherwise specified. MODEL Model 1770 AC INPUT One rear panel mounted switch permits of 115 or 230(240)Vac line voltage. Input Current 115VAC 1.92A 230VAC 0.96A Fuse Rating 11SVAC 4A 230VAC 2A Amplitude 115/230Vac 10% o0r240Vac 10% Frequency 50 to 60 Hz Maximum VA 221VA Maximum Power 192W Peak Inrush Current 30A DC OUTPUT MAXIMUM RATINGS Voltage 0~17.5V ; 0~35V Current 0~6A ; 0~3A DC OUTPUT PROGRAMMING RANGE Voltage 0~17,5V ; 0~35V Current 0~6A ; 0~3A PROGRAMMING RESOLUTION (LSB) Voltage and current programming are monatonic over full temperature range. Voltage 10mV Current 2mA OVP 200mV PROGRAMMING ACCURACY If the unit is recalibrated at a temperature other than 25 C these specifications apply over a temperature band of + 5 C around calibration temperature. Voltage 0.05% +2 LSB Current , 0.15% +5 LSB OVP 2.4% +0.3V LOAD EFFECT Load effect is defined as the maximum change in output due to a load change up to the maximum voltage or current rating. Voltage 0.001% +imV Current lmA Remote sense operation is possible with up to 0.5V drop for positive and negative output load leads. Specifications are subject to change without notice 37APPENDIX A: SPECIFICATIONS (continued) MODEL Model 1770 SOURCE EFFECT Maximum output change for a line voltage change within rating. Voltage ImV Current ImA PARD (PERIODIC AND RANDOM DEVIATION AND NOISE) RMS/PK-PK (20Hz - 20Mhz) with output ungrounded. Voltage 1mVrms/10mVp-p Current lmArms TEMPERATURE COEFFICIENT The temperature coefficient is defined as the change in output per degree Celsius; after a 30 minute warm-up period. Voltage 100ppm/C Current 200ppm/C DRIFT (STABILITY) The drift is defined as the change in output over an eight hour interal under constant line, load, and ambient temperature after a 30 minute warm-up period. Voltage 0.01% + ImV Current 0.1% +6mA LOAD TRANSIENT RESPONSE The time required for the output voltage to recover within a band of 0.1% of rated voltage around the nominal voltage, within a 50% variation in load current. Recovery Time 50us PROGRAMMING UP/DOWN SPEED Tne total programming UP/DOWN time is the sum of output voltage response time and the programming command processing time. LSB is the maximum time for the output voltage to vary within .025% of a final value. UP and DOWN times are the maximum times for the output from 10% to 90% or to 10% of its total excursion value. Tup/Tdn 10ms/15ms LSB 20ms/30ms READBACK RESOLUTION (LSB) Voltage id0mV Current lmA(Low);2mV(High) READBACK ACCURACY If the unit is recalibrated at a temperature other than 25 C, these specifications apply over a temperature band of +t 5 C around calibration temperature. Voltage 0.1% +2LSB Current 0.2% +5LSB READBACK TEMPERATURE COEFFICIENT The readback temperature coefficient is defined as the variation in reading per degree Celsius after a 30 minute warm-up. Voltage 100ppm+10mV Current 200ppm+4mA OUTPUT ISOLATION Neither output terminal may be more than 40Vdc from chassis ground. 240Vdc TEMPERATURE RATINGS Operating 0 C to 50C Storage -40 C to 70C GPIB INTERFACE CAPABILITY SH1,AH1,T6,TEO,L4,LE0,RL1,SR0,PP0,DC1,DT0,C0,E1 WEIGHT 18 lbs DIMENSIONS 8.4" x5.2" x15.7" for all models Specifications are subject to change without notice 38APPENDIX A: SPECIFICATIONS (continued) MODEL Model 1780 Model 1775 AC INPUT One rear panel mounted switch permits operation of 115 or 230(240)Vac line voltage. Input Current 115VAC 2.7A 2.6A 230VAC 135A 13A Fuse Rating AC input is protected by a rear panel mounted fuse. 115VAC 4A 4A 230VAC 2A 2A Amplitude 115/230 Vac 10% or 240 Vac 10% Frequency 50 to 60 Hz Maximum VA 315VA 299VA Maximum Power 240W 232W Peak Inrush Current 30A 30A DC OUTPUT MAXIMUM RATINGS Voltage 18V 35V Current 4A 2A DC OUTPUT PROGRAMMING RANGE Voltage 0-18V 0-35V Current 0-4A 0-2A PROGRAMMING RESOLUTION (LSB) Voltage and current programming are monotonic over full temperature range. Voltage 5mV 10mV Current 1.5mA 0.6mA OVP 100mV 200mV PROGRAMMING ACCURACY If the unit is recalibraed at a temperature other than 25 C, the specifications apply over a temperature band of + 5 C around calibration temperature. Voltage 0.05%+2LSB 0.05%+2LSB Current 0.15%+5LSB 0.15%+5LSB OVP 2.4%+0.6V 2.4%t1.3V LOAD EFFECT Load effect is defined as the maximum change in output due to a load change up to the maximum voltage or current rating. Voltage 0.001%+t1mV 0.001%+1mV Current ImA imA Remote sense operation is possible with up to 0.5V drop for positive and negative output load leads. Specifications are subject to change without notice 39APPENDIX A: SPECIFICATIONS (continued) MODEL Model 1780 Model 1775 SOURCE EFFECT Maximum output change for a line voltage change within rating. Voltage ImV ImV Current 1mA lmA PARD(PERIODIC AND RANDOM DEVIATION AND NOISE) RMS/PK-PK(20Hz -20MHz)with output ungrounded. Voltage ImVrms/l0mVp-p ImVrms/10mVp-p Current imArms imArms TEMPERATURE COEFFICIENT The temperature coefficient is defined as the change in output per degree Celsius; after a 30 minute warm-up period. Voltage 100ppm/C 100ppm/*C Current 200ppm/"C 200ppm/C DRIFT (STABILITY) The drift is defined as the change in output over an eight hour interal under constant line, load, and ambient temperature after a 30 minute warm-up period. Voltage 0.01%+t1mV 0.01%+3mV Current 0.1%+t5mA 0.1%+t2mA LOAD TRANSIENT RESPONSE The time required for the output voltage to recover within a band of 0.1% of rated voltage around the nominal voltage, within a 50% variation in load current. Recovery Time 50us 50us PROGRAMMING UP/DOWN SPEED The total programming UP/DOWN time is the sum of output voltage response time and the programming command processing time. LSB is the maximum time for the output voltage to vary within .025% of a final value. UP and DOWN times are the maximum times for the output from 10% to 90% or to 10% of its total excursion value. Tup/Tdn 10ms/15ms 10ms/15ms LSB 20ms/30ms 20ms/30ms READBACK RESOLUTION Voltage SmV 10mV Current 2mA lmA READBACK ACCURACY . If the unit is recalibrated at a temperature other 25 C these specifications apply over a temperature band of + 5 C around calibration temperature. Voltage 0.1% +2LSB 0.1% +2LSB Current 0.2% +5LSB 0.2% +5LSB READBACK TEMPERATURE COEFFICIENT The readback temperature coefficient is defined as the variation in reading per degree Celsius after a 30 minute warm-up. Voltage 100ppm+4mV 100ppm+8mV Current 200ppm+4mA 200ppm+2mA OUTPUT ISOLATION Neither output terminal may be more than 40Vdc from chassis ground. 240Vdc 240Vdc TEMPERATURE RATINGS Operating 0C to 50C Storage -40 C to 70 C GPIB INTERFACE CAPABILITY SH1,AH1,T6,TEO,L4,LE0,RL1,SRO,PP0,DC1,DT0,CO,E1 WEIGHT 18 Ibs 20 Ibs DIMENSIONS 8.4" x5.2" x15.7" for all models Specifications are subject to change without notice 40APPENDIX B: COMMAND SUMMARIES COMMAND DEFINITION ADDRESS Sets the address of the PPS CALCHNL 0 = end calibration 1 = calibrated channel 1 2 = calibrated channel 2 3 = calibrated all channels IFS Sets the fullscale current for calibration. IOFF Sets the current offset value in calibration. ISET Sets the current ISET1 Sets the current to channel one (Models 1775/1780 only) ISET2 Sets the current to channel two (Models 1775/1780 only) OCP Set the overcurrent protection. OUT Set the output on or off. OUT1 Sets the output of channel one on or off (Models 1775/1780 only) OUT2 Sets the output of channel two on or off (Models 1775/1780 only) OVSET Set the overvoltage protection OVSET1 Set the overvoltage protection value for channel one (Models 1775/1780 only) OVSET2 Set the overvoltage protection value for channel two (Models 1775/1780 only) TRACK Sets the tracking mode of Models 1775/1780. VFS Sets the fullscale voltage for calibration. VOFF Sets the offset voltage for calibration. VSET Sets the voltage VSETI Sets the voltage to channel one (Models 1775/1780 only) VSET2 Sets the voltage to channel two (Models 1775/1780 only) VERSION Display version no. HELP Display command list 41APPENDIX B: COMMAND SUMMARIES COMMAND DEFINITION ERROR Queries for command or numeric errors IOUT Queries the current output. IOUT1 Queries the current output of channel one (Models 1775/1780 only) . IOUT2 Queries the current output channel two (Models 1775/1780 only) ISET? Queries the set current output. ISET1? Queries the set current output of channel one (Models 1775/1780 only) ISET2? Queries the set current output of channel two (Models 1775/1780 only) OVSET? Queries the overvoltage value. OVSET1? Queries the overvoltage value for channel one (Models 1775/1780 only) OVSET2? Queries the overvoltage value for channel two (Models 1775/1780 only) STATUS Queries the status of the power supply.(see note 3 ) VOUT Queries the output voltage. VOUT1 Queries the output voltage of channel one (Models 1775/1780 only) VOUT2 Queries the output voltage of channel two (Models 1775/1780 only) VSET? Queries the set voltage value VSET1? Queries the set voltage value of channel one (Models 1775/1780 only) VSET2? Queries the set voltage value of channel two (Models 1775/1780 only) RANGE 0 = low current 1 = high current OVP Set the overvoltage protection MODEL Queries the model no. of the power supply. BEEP 0 = beeper function disable 1 = beeper function disable 2 = force beeper alarm 3 = beeper alarm off 42APPENDIX C: QUERY MESSAGES ERROR CODE MESSAGE DEFINITION ERROR 0 No Errors ERROR 1 Command String Error ERROR 2 Numeric String out of Range ERROR 3 Numeric String Over Length ERROR 4 Command Sequence Error ERROR 5 ERROR 6 NOTE: 1. All GPIB commands are case-nonsensitivity ASCII codes. 2. Allow many command string 3. STATUS operation explanation: After "STATUS" command accepted, PPS will display a decimal number in ASCII, convert this decimal this decimal number to binary form. Each bit indicated a action/status: (Channel 1------ > CH1, Channel 2------ > CH2) bit 0: 0 NO ERROR 1 ERROR bit 1: 0 CH1 OUTPUT OFF 1 CH1 OUTPUT ON bit 2: 0 CH1 OCP ON 1 CH1 OCP OFF bit 3: 0 CH1OC NOT OCCUR 1 CH1 OC OCCUR bit 4: 0 CH1 OV NOT OCCUR 1 CH1 OV OCCUR bit 5: 0 CH1 CV MODE 1 CH1 CC MODE bit 6: 0 LOW RANGE 1 HIGH RANGE bit 7: 0 BEEPER ON 1 BEEPER OFF bit 8: 0 ARROW IN CHANNEL 1 1 ARROW IN CHANNEL 2 bit 9: 0 CH2 OUTPUT OFF 1 CH2 OUTPUT ON bit 10: 0 CH2 OCP ON 1 CH2 OCP OFF bit 11: 0 CH2 OC NOT OCCUR 1 CH2 OC OCCUR bit 12: 0 CH2 OV NOT OCCUR 1 CH2 OV OCCUR bit 13: 0 CH2 CV MODE 1 CH2 CC MODE bit 14: 0 INDEPENDENT 1 TRACKING TO CHANNEL 1 bit 15: 0 RESERVED 43APPENDIX D: QUERY MESSAGES The following is a software calibration program written in QBASIC for an one channel PROGRAMMABLE DC POWER SUPPLY. The equipment necessary to calibrated the unit included a PPS series (relay control), a FLUKE 8842A digital multimeter (GPIB interface), and a controller card from National Instruments (AT-GPIB). A shunt resistor used for local calibration may be utilized in remote calibration. '***program and variable declaration *** DECLARE SUB DELAY (SECONDS) MULTIPLIER = 10 dmm$ = ~ 20 :CH$= ~~ '** program initialization *** RANDOMIZE TIMER OPEN ~ gpib0- FOR OUTPUT AS #1 OPEN ~ gpib0- FOR INPUT AS #2 PRINT #1, - ABORT- PRINT #1, > REMOTE- PRINT #1, clear- PRINT #1, ~ output ; dmm$;~ ;* ~ PRINT #1, - OUTPUTI,OUTO ; VEST 6; ISET 0.125 ~ CLS INPUT ~ Enter GPIB address of PPS unit under test (default = 12) = ~ ;pps$ IF VAL{pps$)<0 OR VAL (pps$)>31 OR pps$ = ~~ THEN pps$ =~ 12 ~ PRINT #1, -output-; pps$; - ;model?~ PRINT #1, ~ enter ~ ;pps$ INPUT #2, model$ PRINT : print ~ ~; model$ ~ found at GPIB address ~ ;pps$ PRINT DO INPUT~ Enter channel for calibration/testing (1/2) = > - ;CH$ LOOP UNTIL CH$ =~ 1- OR CH$ =~ 2 ~ PRINT #4 VOLTAGE CALIBRATION **#** PRINT #1, ~ output ~ ; pps$; ~ ; calchni1~ CALL DELAY(3) PRINT#1, ~ enter ~ ;dmm$: INPUT #2, rd$ voff = VAL(rd$) PRINT #1, ~ output ~ ; ppsS, ~ ;voff ~; STRS(voff) CALL DELAY(3) PRINT#1, ~ enter ~ ;dmm$: INPUT #2, rd$ vfs = VAL(rd$) PRINT#1, ~ output ~ ; pps$; - ;vfs ~ ;STRS(vfs) PRINT USING ~ Offset Voltage = ##.4## V Fullscale Voltage = ##.4## V - ; voff; vfs tke CURRENT CALIBRATION ***** PRINT#1, - outputl ; out 1 ~ CALL DELAY(3) PRINT# 1, ~ enter ~ ;dmm$: INPUT #2, rd$ ioff = VAL(rd$)* MULTIPLIER PRINT#1, ~ output ~ ;pps$; ~ jioff - ; STR$ (ioff) CALL DELAY (3) PRINT#1, ~ enter ~ ;dmm$: INPUT #2, rd$ ifs = VAL(rd$) * MULTIPLIER PRINTH#I, " output " :pps$; "; ifs"; STRS(ifs) PRINT USING - Offset Current = ##.44# V Fullscale Counter = #.4### A; ioff; ifs CALL DELAY (5) PRINT#1, ~ enter ~ PRINT#1, ~ LOCAL~ END SUB DELAY(SECONDS) FOR count = 1 TO 5000 * SECONDS NEXT count END SUB 44SAFETY PRECAUTIONS SAFETY PRECAUTIONS The B+K Precision Programmable Power Supply have been designed and tested according to EN-61010-1, Safety requirement for Electronic Measuring Apparatus. SAFETY NOTES The following general safety precautions must be observed during all phases of operation, service, and repair of this instrument. Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design, manufacture, and intended use of the instrument. The manufacturer assumes no liability for the customer's failure to comply with these requirements. BEFORE APPLYING POWER ZN Verify that the product is set to match the available line voltage and the correct fuse is installed. GROUND THE INSTRUMENT This product is provided with a protective earth terminal. To minimize shock hazard, the instrument chassis and cabinet must be connected to an electrical ground. The instrument must be connected to the AC power supply mains through a three-conductor power cable, with the third wire firmly connected to an electrical ground (safety ground) at the power outlet. For instruments designed to be hard-wired to the ac power lines (supply mains), connect the protective earth terminal to a protective conductor before any other connection is made. Any interruption of the protective (grounding) conductor or disconnection of the protective earth terminal will cause a potential shock hazard that could result in personal injury. If the instrument is to be energized via an external autotransformer for voltage reduction, be certain that the autotransformer common terminal is connected to the neutral (earthed pole) of the ac power lines (supply mains). The GPIB (option) Ground is connected with chassis ground, and therefore the operator must take care if the computer is also connected with other measuring devices prevent a short cut. FUSES Only fuses with the required current, voltage, and specified type (normal blow, time delay, etc.) should be used. Do not use repaired fuses or short circuited fuseholders. To do so could cause a shock or fire hazard. KEEP AWAY FROM LIVE CIRCUITS Operating personnel must not remove instrument covers. Component replacement and internal adjustment must be made by qualified service personnel. Do not replace components with power cable connected. Under certain conditions, dangerous voltage may exist even with the power cable removed. To avoid injuries, always disconnect power, discharge circuits and remove external voltage sources before touching components. DO NOT SERVICE OR ADJUST ALONE Do not attempt internal service or adjustment unless another person, capable of rendering first aid and resuscitation, is present. DO NOT EXCEED INPUT RATINGS This instrument must be connected to a properly grounded receptacle to minimize electric shock hazard. Operation at line voltage or frequencies in excess of those stated on the data plate may cause leakage currents in excess of 5.0mA peak. 45