Like the Jrk 12v12, the JRK 21v3 is a very well
thought-out motor controller. It's like a little brother - similar
characteristics, but not quite as strong. It's ideal for small motors.
Nice work, Pololu!
Where the 12v12 is rated 16V and 12A continous output, the 21v3
is rated 28V and 3A.
Almost every other feature of the 12v12 implemented in the 21v3 (the
exception being the current sensor being 0.5V per amp).
Main points of interest:
- 5 to 28 VDC power input
- 3A with 5A surge current rating
- Can be controlled via:
- USB
- PWM (servo remote control style)
- Analog joystic/potentiometer
- Optional Feedback control via:
- 0-5V analog input
- Frequency signal (like a tachometer)
- Calibrate with USB interface to Windows software
- Configure feedback loops via software with control over
- PID period & constants. (Proportional / Integral
/ Derivative - embedded!)
- Error response
- Learning calibration for RC / Analog interfaces
- Programmable maximum
- Current
- Duty cycle
- Acceleration
WOW - that's a huge bundle of features for a compact unit measuring
only 1.35" x 1.35" x 0.4"!
So what make is so superior to other models of motor driver units?
- Control the motor via a
PC's USB port (as simulated serial interface)
- Ultrasonic PWM
to eliminate switching-induced motor shaft hum or whine.
- Robust, high-speed communication protocol with
user-configurable error condition response.
- 12-bit resolution (that's 4096 levels) for smooth and
flexible
calibration to various input and feedback devices.
- Current sensing and limiting.
- Reversed power protection.
- Field-upgradeable firmware.
The only serious limit to this unit is that it is a single
motor driver. Not dual. So if you want to drive a robot,
you'll need one of these per motor. But with this feature set, it'll be
very easy to work with!
Specifications:
| Motor channels: |
1 |
| Operating voltage: |
5 – 28 V |
| Continuous output current: |
3 A |
| Peak output current: |
5 A |
| Auto-detect baud rate range: |
300 – 115,200 bps |
| Available fixed baud rates: |
300 – 115,200 bps |
| Available PWM
frequencies: |
20 kHz, 5 kHz |
| Reverse voltage protection?: |
Yes |
| USB
connector style: |
USB Mini-B |
Included Hardware:
The jrk ships with a 14×1 straight 0.100" male
header strip
and two 5mm, 2-pin terminal blocks. To provide maximum flexibility,
none of these parts are soldered to the board.
For the most compact installation, you can solder wires directly to the
jrk pads themselves and skip using the included hardware. The included
hardware allows you to make less permanent connections. You can break
the 14×1 header strip into an 8×1 piece and two
3×1 pieces and solder
these strips into the jrk’s I/O pads.
Note:USB cable not
included.
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