Pololu G2 User manual

Pololu Simple Motor Controller
2 User’s uide
Pololu Simple Motor ontroller G2 User’s Guide © 2001–2019 Pololu orporation
https://www.pololu.com/docs/0J77/all Page 1 of 143

1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. 18v15 and 24v12 included hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.2. 18v25 and 24v19 included hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.3. Supported operating systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.4. omparison to the original Simple Motor ontrollers . . . . . . . . . . . . . . . . . . . 12
2. ontacting Pololu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3. Getting started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1. Installing Windows drivers and software . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.2. Understanding the control center Status tab . . . . . . . . . . . . . . . . . . . . . . . 18
3.3. Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.5. LED feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4. onnecting your motor controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.1. onnecting power and a motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
4.2. Serial/I² interface pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.3. onnecting a serial device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.4. onnecting an I² device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.5. onnecting an R receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.6. onnecting a potentiometer or analog joystick . . . . . . . . . . . . . . . . . . . . . . 46
5. onfiguring your motor controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5.1. Input settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5.1.1. onfiguring a limit or kill switch . . . . . . . . . . . . . . . . . . . . . . . . . . 57
5.2. Motor settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
5.3. Advanced settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
5.4. Upgrading firmware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
6. Using the serial and I² interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
6.1. Serial and I² settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
6.2. Binary commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
6.2.1. Binary command reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
6.3. AS II commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
6.3.1. AS II command reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
6.4. ontroller variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
6.5. yclic redundancy check ( R ) error detection . . . . . . . . . . . . . . . . . . . . 103
6.6. Serial daisy chaining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
7. Writing P software to control the Simple Motor ontroller G2 . . . . . . . . . . . . . . . . 108
8. Example code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Pololu Simple Motor ontroller G2 User’s Guide © 2001–2019 Pololu orporation
Page 2 of 143

8.1. Example code to run smcg2cmd in . . . . . . . . . . . . . . . . . . . . . . . . . . 109
8.2. Example code to run smcg2cmd in Python . . . . . . . . . . . . . . . . . . . . . . . . 110
8.3. Example native USB code in #, Visual ++, and VB .NET . . . . . . . . . . . . . . . 111
8.4. Example serial code for Arduino . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
8.5. Example serial code for Orangutan . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
8.6. Example serial code for Linux and macOS in . . . . . . . . . . . . . . . . . . . . . 123
8.7. Example serial code for Windows in . . . . . . . . . . . . . . . . . . . . . . . . . 128
8.8. Example serial code in Python . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
8.9. Example serial code for Linux or macOS in Bash . . . . . . . . . . . . . . . . . . . . 134
8.10. Example I² code for Arduino . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
8.11. Example I² code for Linux in . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
8.12. Example I² code for Linux in Python . . . . . . . . . . . . . . . . . . . . . . . . . 140
8.13. Example R computation in . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Pololu Simple Motor ontroller G2 User’s Guide © 2001–2019 Pololu orporation
Page 3 of 143

ide-by-side comparison of the different
G2 imple Motor Controllers.
1. Overview
The second-generation G2 Simple Motor ontrollers are
versatile, general-purpose motor controllers for brushed,
D motors. Wide operating voltage ranges and the ability
to deliver up to several hundred Watts in a small form
factor make these controllers suitable for many motor
control applications. With a variety of supported
interfaces—USB for direct connection to a computer, TTL
serial and I² for use with embedded systems, R hobby
servo pulses for use as an R -controlled electronic
speed control (ES ), and analog voltages for use with a potentiometer or analog joystick—and a wide
array of configurable settings, these motor controllers make it easy to add basic control of brushed D
motors to a variety of projects. A free configuration utility for Windows simplifies initial setup of the
device and allows for in-system testing and monitoring of the controller via USB.
The table below lists the members of the Simple Motor ontroller G2 family and shows the key
differences among them:
18v15 24v12 18v25 24v19
Minimum
operating voltage: 6.5 V 6.5 V 6.5 V 6.5 V
Recommended max
operating voltage: 24 V(1) 34 V(2) 24 V(1) 34 V(2)
Max nominal
battery voltage: 18 V 28 V 18 V 28 V
Max continuous current
(no additional cooling): 15 A 12 A 25 A 19 A
Dimensions: 2.1″ × 1.1″ 1.7″ × 1.2″
Available with
connectors installed? Yes Yes No No
130 V absolute max.
240 V absolute max.
Pololu Simple Motor ontroller G2 User’s Guide © 2001–2019 Pololu orporation
1. Overview Page 4 of 143

High-Power imple Motor Controller G2 18v25 or 24v19 simplified
connection diagram.
Key features
• Simple bidirectional control of one D brush motor.
• Five communication or control options:
1. USB interface for direct connection to a P .
2. Logic-level (TTL) serial interface for use with a microcontroller.
3. I² interface for use with a microcontroller.
4. Hobby radio control (R ) pulse width interface for direct connection to an R
receiver or RC servo controller [https://www.pololu.com/category/12/rc-servo-controllers].
5. 0 V to 3.3 V analog voltage interface for direct connection to potentiometers and
analog joysticks.
• Simple configuration and calibration over USB with a free configuration program for Windows
• Reverse-voltage protection
• Hardware current limiting with a configurable threshold
• urrent sensing
Note: AUSB A to Micro-B cable [https://www.pololu.com/product/2073] (not included) is
required to connect this controller to a computer.
Additional features
• Adjustable maximum acceleration and deceleration to limit electrical and mechanical stress
Pololu Simple Motor ontroller G2 User’s Guide © 2001–2019 Pololu orporation
1. Overview Page 5 of 143

on the system.
• Adjustable starting speed and maximum speed.
• Option to brake or coast when speed is zero.
• Optional safety controls to avoid unexpectedly powering the motor.
• Input calibration (learning) and adjustable scaling degree for analog and R signals.
• Under-voltage shutoff with hysteresis for use with batteries vulnerable to over-discharging
(e.g. LiPo cells).
• Adjustable over-temperature threshold and response.
• Adjustable PWM frequency from 1.13 kHz to 22.5 kHz (maximum frequency is ultrasonic,
eliminating switching-induced audible motor shaft vibration).
• Error LED linked to a digital ERR output, and connecting the error outputs of multiple
controllers together optionally causes all connected controllers to shut down when any one
of them experiences an error.
• Field-upgradeable firmware.
•Features of the serial, I²C, and USB interfaces:
◦ Optional R error detection to eliminate communication errors caused by noise or
software faults.
◦ Optional command timeout (shut off motors if communication ceases).
•Serial features:
◦ ontrollable from a computer via serial commands sent to the device’s USB virtual
serial ( OM) port, or via TTL serial through the device’s RX/TX pins.
◦ TTL serial uses 0 V and 3.3 V on TX, accepts 0 V to 5 V on RX.
◦ Supports automatic baud rate detection from 1200 bps to 500 kbps, or can be
configured to run at a fixed baud rate.
Pololu Simple Motor ontroller G2 User’s Guide © 2001–2019 Pololu orporation
1. Overview Page 6 of 143

◦ Supports standard compact and Pololu protocols as well as the Scott Edwards
Mini SS protocol and an AS II protocol for simple serial control from a terminal
program.
◦ Optional serial response delay for communicating with half-duplex controllers such
as the Basic Stamp.
◦ ontrollers can be easily chained together and to other Pololu serial motor and
servo controllers to control hundreds of motors using a single serial line.
•I²C features:
◦ ompatible with I² bus voltage levels from 1.8 V to 5 V.
•USB features:
◦ Full-speed USB interface (12 Mbps)
◦ Example code in #, Visual Basic .NET, and Visual ++ is available in the Pololu
USB Software Development Kit [https://www.pololu.com/docs/0J41]
•RC features:
◦ 1/4 µs pulse measurement resolution.
◦ Works with R pulse frequencies from 10 to 333 Hz.
◦ onfigurable parameters for determining what constitutes an acceptable R signal.
◦ Two R channels allow for single-stick (mixed) motor control, making it easy to use
two simple motor controllers in tandem on an R -controlled differential-drive robot.
◦ R channels can be used in any mode as limit or kill switches (e.g. use an R
receiver to trigger a kill switch on your autonomous robot).
◦ Battery elimination circuit (BE ) jumper can power the R receiver with 5 V or 3.3 V.
•Analog features:
◦ 0.8 mV (12-bit) measurement resolution.
◦ Works with 0 to 3.3 V inputs.
◦ Optional potentiometer/joystick disconnect detection.
◦ Two analog channels allow for single-stick (mixed) motor control, making it easy to
use two simple motor controllers in tandem on a joystick-controlled differential-drive
robot.
◦ Analog channels can be used in any mode as limit or kill switches.
Pololu Simple Motor ontroller G2 User’s Guide © 2001–2019 Pololu orporation
1. Overview Page 7 of 143

Note: This guide only applies to the G2 Simple Motor ontrollers, which have blue circuit
boards. If you have one of the first-generation Simple Motor ontrollers, which have
green circuit boards, you can find their user’s guide here [https://www.pololu.com/docs/0J44].
Warning: Take proper safety precautions when using high-power electronics. Make sure
you know what you are doing when using high voltages or currents! During normal
operation, this product can get hot enough to burn you. Take care when handling this
product or other components connected to it.
1.1. 18v15 and 24v12 included hardware
High-Power imple Motor Controller G2
18v15 with included hardware.
High-Power imple Motor Controller G2
24v12 with included hardware.
High-Power imple Motor Controller G2
18v15 with connectors soldered.
High-Power imple Motor Controller G2
24v12 with connectors soldered.
Pololu Simple Motor ontroller G2 User’s Guide © 2001–2019 Pololu orporation
1. Overview Page 8 of 143

High-Power imple Motor Controller G2 18v15 or 24v12,
bottom view with dimensions.
Pinout diagram of the High-Power imple Motor Controller G2 18v15 or 24v12.
The 18v15 and 24v12 versions are available with connectors included but not soldered in or with the
connectors pre-installed.
The terminal blocks are only rated for 16 A, so for higher-power applications, we recommend soldering
thick wires directly to the board.
These files provide further documentation of the hardware design of the Simple Motor ontroller G2
18v15 and 24v12:
•Dimension diagram [https://www.pololu.com/file/0J1600/pololu-smc-
g2-18v15-or-24v12-dimensions.pdf] (424k pdf)
•3D model [https://www.pololu.com/file/0J1602/pololu-smc-g2-18v15-or-24v12.step] (12MB step)
Pololu Simple Motor ontroller G2 User’s Guide © 2001–2019 Pololu orporation
1. Overview Page 9 of 143

•Drill guide [https://www.pololu.com/file/0J1601/umc08a-drill.dxf] (100k dxf)
1.2. 18v25 and 24v19 included hardware
High-Power imple Motor Controller G2
18v25 with included hardware.
High-Power imple Motor Controller G2
24v19 with included hardware.
High-Power imple Motor Controller G2
18v25 with connectors soldered.
High-Power imple Motor Controller G2
24v19 with connectors soldered.
High-Power imple Motor Controller G2
18v25, bottom view with dimensions.
High-Power imple Motor Controller G2
24v19, bottom view with dimensions.
Pololu Simple Motor ontroller G2 User’s Guide © 2001–2019 Pololu orporation
1. Overview Page 10 of 143