BIDIR-115D(S) Speed Controller
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15 Amp Bidirectional Digital PWM Motor Speed Controller
BIDIR-115D and BIDIR-115DS
The BIDIR-115D(S) allows you to control the speed and direction of a motor using an analog
voltage input, push buttons, or digital logic pulses. Use of PWM and low on-resistance MOSFETs
allows for high efficiency control with minimal loss of power.
Absolute Maximum Ratings:
Parameter Max Units
Continuous Output Current 15 A
Instantaneous Output Current 20 A
Input Voltage 30 V
Warning – operating at or above the absolute maximum ratings may damage your controller or
your equipment under control.
Operating Parameters:
Parameter Min Typical Max Units
Input Voltage 10 12 26 V
Continuous Output Current -- -- 15 A
Digital Logic Input Low Level 0 -- 1.5 V
Digital Logic Input High Level 3.5 -- 5 V
Digital Input Capacitance -- 0.1 -- uF
Analog Voltage Input 0 -- 5 V
Potentiometer Total Resistance 1 10 30 kΩ
Digital Continuous Mode Change Rate -- 33 -- % / s
Soft Start from Disabled Mode, Ramp Rate -- 100 -- % / s
PWM Frequency 150 200 250 Hz
Quiescent Current Drain 70 75 80 mA
Temperature -40 25 +60 °C
Pin-out:
Pin Label Function Active H/L Mode
P- Lower pin of potentiometer (GND)
-- Analog
DN/CN Wiper of potentiometer (analog)
Decrease Pulse Width (digital)
(internal pull-up in digital mode) L = decrease (digital) Both
P+ Upper pin of potentiometer (5V)
-- Both
UP Increase Pulse Width
(internal pull-up) L = increase Digital
DIR Direction
L = forward
H = reverse Both
EN PWM output enable
(internal pull-up) H = enable
L = disable Both
M - Negative output to LOAD
-- Both
M + Positive output to LOAD
-- Both
GND Ground from power supply
-- Both
V+ Positive Power Supply
-- Both
BIDIR-115D(S) Speed Controller
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Modes of Operation:
The Analog/Digital PWM Controller can be operated in analog or digital mode. The jumper
labeled P/D (JP1) is used to select between analog and digital inputs. Jumper CLKED is used to
select between clocked digital speed selection and continuous digital speed selection (or push
button mode).
Table 1: Jumper Configuration
Jumper Label Position Function
P/D (JP1)
Closed
Potentiometer
(Analog Mode)
P/D (JP1)
Open
Digital Mode
CLKED (JP2)
Closed
Clocked Digital
CLKED (JP2)
Open
Continuous Digital
(Push Button Mode)
Note: All jumper setting changes take effect at power-up. Power down the board before changing the
jumper settings.
Analog Mode:
When the board is configured for Analog Operation using the jumper, a varying voltage (0 – 5 V)
level is converted to the pulse width at the output (0 – 100%). Any potentiometer from 1kΩ - 30
kΩ may be used for speed control.
There is a built-in dead-band for potentiometer operation that sets the duty cycle to:
0% for any voltage level < 0.10 V.
100% for any voltage level > 4.90 V.
This dead-band along with digital filtering ensures smooth and reliable operation even with dirty
potentiometers.
A switch can be connected between the DIR input and P+ to reverse the direction of the motor.
Ensure that the motor is completely stopped before reversing direction. The onboard fuse
protects the motor in the event of an accidental reverse when the motor is still rotating. Replace
only with a fuse of the same type and rating.
BIDIR-115D(S) Speed Controller
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Digital Mode:
There are two ways to operate in digital mode: Clocked Mode and Continuous Mode.
Clocked Mode:
In clocked mode, the UP and DN inputs are used to control the duty cycle. For every
rising edge of the UP [DN] line, the output pulse width is increased [decreased] by
approximately 0.8%. Once the pulse width reaches 0%, any further inputs on the DN
line have no effect. Similarly, when the pulse width reaches 100%, any further inputs on
the UP line have no effect.
Continuous Mode:
In continuous mode, the UP and DN inputs are designed for interfacing to push buttons.
When the UP line is brought LOW, the duty cycle is continuously increased at a rate of ~
33% per second. Similarly, when the DN line is brought low, the duty cycle is decreased
at a rate of ~ 33% per second. Any additional increase [decrease] after the pulse width
has reached 100% [0%] will have no effect on the output.
Automatic digital de-bouncing of the inputs is implemented in continuous mode. Spurious
inputs are ignored.
Output Enable:
The output is enabled by default and is internally pulled up. Bringing this pin low immediately
brings the PWM output to 0%. Allowing the pin to go back to high re-enables the PWM output at
the previous duty cycle.
When in digital mode, the duty cycle may be changed by the UP and DN pins at all times, even in
PWM output disabled mode. Thus, it is possible to turn off the output, change the duty cycle, and
turn on the output again, but at the new duty cycle.
Reversing:
A 0-5V digital signal can be sent to the DIR input to reverse the direction of the motor. If using
continuous mode, a switch can be connected between P+ and DIR instead for reversing control.
Ensure that the motor is completely stopped before reversing direction. The onboard fuse
protects the motor in the event of an accidental reverse when the motor is still rotating. Replace
only with a fuse of the same type and rating.
Soft Start (BIDIR-115DS only):
The output is automatically ramped up back to the full PWM level at a rate of 100% per second.
This reduces the stress placed on power supplies and mechanical linkages as motors come back
up to speed.
BIDIR-115D(S) Speed Controller
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Connection Diagrams:
BIDIR-115D(S) Speed Controller
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BIDIR-115D(S) Speed Controller
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Application Notes:
The controller automatically puts the motor into braking mode when power is removed. Please be
aware that if the motor is still spinning when the power is removed , the motor will brake
suddenly.
PWM controllers switch currents at high frequencies to vary the average power to the load. This
switching can cause undesirable RF interference. To minimize such interference, it is
recommended to twist the input V+ and Ground wire pair as well as the Out+ and Out- wire pair.
In addition, installation of a small capacitor from each of the two motor terminals to the metal
case may reduce noise emission.
A fuse appropriately rated for the load device can help enhance safety.
This controller is not reverse-polarity protected. Ensure that it is wired correctly before applying
power. Always turn off the power supply before making any changes to the wiring.
Ensure that the controller has adequate air flow for proper cooling. If operating for extended
periods of time in high temperature environments, a cooling fan may be necessary.
Use the shortest possible wires between the motor and controller, and between the controller
and the power source. Ensure that the wires carrying the load current are adequately sized. If
operating heavy inductive loads, it may be advisable to add an appropriately rated filter capacitor
at the input to the PWM controller. Inadequate power supply filtering or other causes leading to a
high impedance path to the power supply will result in higher losses in the filter capacitor and
wiring, reducing overall system efficiency.
30-Day Limited Warranty:
Subject to the provisions described below, CRITICAL VELOCITY ENTERPRISES, LLC (“Critical Velocity”) warrants this product to be free
from defects in material and workmanship for thirty (30) days from the date of purchase by the original consumer. If any part is found to
be defective during the warranted period, it will be repaired or replaced with the same or functionally equivalent product by Critical Veloci ty,
at its discretion, free of charge provided you: (1) return the failed pro duct to Critica l Ve lo city with shipping prepaid, a n d ( 2) provide Crit ica l
Velocity with proof of the original date of purchase. Repaired or replacement products will be returned to you with shipping charges
prepaid.
Replacement products may be refurbished or contain refurbished materials. If Critical Velocity, by its sole determination, is unable to repair
or replace the defective product, it will refund the purchase price of the product. This warranty does not apply if, in the judgment of Critical
Velocity, the product fails due to damage from shipment, handling, storage, accident, abuse or misuse, or if it has been used or maintained
in a manner not conforming to product manual instructions or has been modified in any way. Repair by anyone other than Critical Velocity
will void this warranty. The maximum liability of Critical Velocity under this warranty is limited to the purchase price of the product covered
by the warranty.
Except as specifically provided in this agreement or as required by law, the warranties and remedies stated above are exclusive and in lieu
of all others, oral or written, express or implied. Any and all other warranties, i n cluding implied warranties of merchanta bility, fitness for a
particular purpose and noninfringement of third party rights are expressly excluded. Critical Velocity shall not under any circumstances be
liable for any special, incidental, indirect or consequential damages, including without limitation, damages resulting from use or malfunction
of the products, loss of profits or revenues or costs of replacement goods, even if Critical Velocity is informed in advance of the possibility
of such damages.
LIFE SUPPORT POLICY:
Critical Velocity’s products are not authorized for use as critical components in life support devices or systems. As used herein:
1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or
sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be
reasonably expected to result in a significant injury of the user.
2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause
the failure of the life support device or system, or to affect its safety or effectiveness.
