RoboteQ AX2850 User Manual
AX2550
AX2850
Dual Channel
High Power
Digital Motor
Controller
User’s Manual
v1.9b, June 1, 2007
visit www.roboteq.com to download the latest revision of this manual
©Copyright 2003-2007 Roboteq, Inc.
2 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
Revision History
Revision History
Date Version Changes
June 1, 2007 1.9b Added Output C active when Motors On
Fixed Encoder Limit Switches
Protection in case of Encoder failure in Closed Loop Speed
Added Short Circuit Protection (with supporting hardware)
Added Analog 3 and 4 Inputs (with supporting hardware)
Added Operating Mode Change on-the-fly
Changeable PWM frequency
Selectable polarity for Dead Man Switch
Modified Flashing Pattern
Separate PID Gains for Ch1 and C2, changeable on-the-fly
Miscellaneous additions and correction
Added Amps Calibration option
January 10, 2007 1.9 Changed Amps Limit Algorithm
Miscellaneous additions and correction
Console Mode in Roborun
March 7, 2005 1.7b Updated Encoder section.
February 1, 2005 1.7 Added Position mode support with Optical Encoder
Miscellaneous additions and corrections
April 17, 2004 1.6 Added Optical Encoder support
March 15, 2004 1.5 Added finer Amps limit settings
Enhanced Roborun utility
August 25, 2003 1.3 Added Closed Loop Speed mode
Added Data Logging support
Removed RC monitoring
August 15, 2003 1.2 Modified to cover AX2550 controller design
Changed Power Connection section
April 15, 2003 1.1 Added analog mode section
Added position mode section
Added RCRC monitoring feature
Updated Roborun utility section
Modified RS232 watchdog
March 15, 2003 1.0 Initial Release
The information contained in this manual is believed to be accurate and reliable. However,
it may contain errors that were not noticed at time of publication. User’s are expected to
perform their own product validation and not rely solely on data contained in this manual.
AX2550 Motor Controller User’s Manual 3
4 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
Revision History 3
SECTION 1 Important Safety Warnings 13
This product is intended for use with rechargeable batteries 13
Do not Connect to a RC Radio with a Battery Attached 13
Beware of Motor Runaway in Improperly Closed Loop 13
SECTION 2 AX2550
Quick Start 15
What you will need 15
Locating the Switches, Wires and Connectors 15
Connecting to the Batteries and Motors 17
Connecting to the 15-pin Connector 18
Connecting the R/C Radio 19
Powering On the Controller 20
Button Operation 20
Default Controller Configuration 21
Connecting the controller to your PC using Roborun 22
Obtaining the Controller’s Software Revision Number 23
Exploring further 24
SECTION 3 AX2550 Motor Controller Overview 25
Product Description 25
Technical features 26
SECTION 4 Connecting Power and Motors to the Controller 29
Power Connections 29
Controller Power 30
Controller Powering Schemes 32
Powering the Controller from a single Battery 32
Powering the Controller Using a Main and Backup Battery 33
Connecting the Motors 34
Single Channel Operation 35
Converting the AX2550 to Single Channel 35
Power Fu ses 36
Wire Length Limits 37
Electrical Noise Reduction Techniques 37
Power Regeneration Considerations 37
Overvoltage Protection 38
Undervoltage Protection 38
Using the Controller with a Power Supply 39
AX2550 Motor Controller User’s Manual 5
SECTION 5 General Operation 41
Basic Operation 41
Input Command Modes 41
Selecting the Motor Control Modes 42
Open Loop, Separate Speed Control 42
Open Loop, Mixed Speed Control 42
Closed Loop Speed Control 43
Close Loop Position Control 43
User Selected Current Limit Settings 44
Temperature-Based Current Limitation 44
Battery Current vs. Motor Current 45
Regeneration Current Limiting 46
Programmable Acceleration 47
Command Control Curves 48
Left / Right Tuning Adjustment 49
Activating Brake Release or Separate Motor Excitation 51
Emergency Shut Down Using Controller Switches 51
Emergency Stop using External Switch 51
Inverted Operation 52
Special Use of Accessory Digital Inputs 52
Using the Inputs to Activate the Buffered Output 52
Using the Inputs to turn Off/On the Power MOSFET
transistors 52
Self-Test Mode 53
SECTION 6 Connecting Sensors and Actuators to Input/Outputs 55
AX2550 Connections 55
AX2550’s Inputs and Outputs 57
I/O List and Pin Assignment 58
Connecting devices to Output C 59
Connecting Switches or Devices to Input E 60
Connecting Switches or Devices to Input F 61
Connecting Switches or Devices to EStop/Invert Input 62
Analog Inputs 63
Connecting Position Potentiometers to Analog Inputs 63
Connecting Tachometer to Analog Inputs 64
Connecting External Thermistor to Analog Inputs 66
Using the Analog Inputs to Monitor External Voltages 67
Connecting User Devices to Analog Inputs 67
Internal Voltage Monitoring Sensors 68
Internal Heatsink Temperature Sensors 68
Temperature Conversion C Source Code 69
6 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
SECTION 7 Installing, Connecting and Using the Encoder Module 71
Optical Incremental Encoders Overview 71
Recommended Encoder Types 72
Installing the Encoder Module 73
Connecting the Encoder 75
Cable Length and Noise Considerations 76
Motor - Encoder Polarity Matching 76
Voltage Levels, Thresholds and Limit Switches 76
Wiring Optional Limit Switches 78
Wiring Limit Switches Without Encoders 79
Effect of Limit Switches 79
Using the Encoder Module to Measure Distance 80
Using the Encoder to Measure Speed 80
Using the Encoder to Track Position 81
RS232 Communication with the Encoder Module 82
Encoder Testing and Setting Using the PC Utility 83
SECTION 8 Closed Loop Position Mode 85
Mode Description 85
Selecting the Position Mode 85
Position Sensor Selection 86
Sensor Mounting 86
Feedback Potentiometer wiring 87
Feedback Potentiometer wiring in RC or RS232 Mode 87
Feedback Potentiometer wiring in Analog Mode 88
Analog Feedback on Single Channel Controllers 89
Feedback Wiring in RC or RS232 Mode on Single Channel
Controllers 89
Feedback Wiring in Analog Mode on Single Channel
Controllers 89
Using Optical Encoders in Position Mode 90
Sensor and Motor Polarity 90
Encoder Error Detection and Protection 91
Adding Safety Limit Switches 91
Using Current Limiting as Protection 93
Control Loop Description 93
PID tuning in Position Mode 94
SECTION 9 Closed Loop Speed Mode 97
Mode Description 97
Selecting the Speed Mode 97
Using Optical Encoder for Speed Feedback (AX2850 only) 98
AX2550 Motor Controller User’s Manual 7
Tachometer or Encoder Mounting 98
Tachometer wiring 98
Speed Sensor and Motor Polarity 99
Adjust Offset and Max Speed 100
Control Loop Description 100
PID tuning in Speed Mode 10 2
SECTION 10 Normal and
Fault Condition LED Messages 103
Use of the LED Display 103
Motor Direction Status 104
Fault Messages 105
No Control 105
Tem po ra r y F a u lt s 106
Permanent Faults 106
Self-Test Display 106
SECTION 11 R/C Operation 109
Mode Description 109
Selecting the R/C Input Mode 110
Connector I/O Pin Assignment (R/C Mode) 110
R/C Input Circuit Description 111
Supplied Cable Description 111
Powering the Radio from the controller 11 2
Connecting to a Separately Powered Radio 114
Operating the Controller in R/C mode 11 4
Reception Watchdog 115
R/C Transmitter/Receiver Quality Considerations 116
Joystick Deadband Programming 117
Command Control Curves 11 8
Left/Right Tuning Adjustment 118
Joystick Calibration 11 8
Automatic Joystick Calibration 119
Activating the Accessory Outputs 120
Data Logging in R/C Mode 121
SECTION 12 Analog Control and Operation 123
Mode Description 123
Connector I/O Pin Assignment (Analog Mode) 124
Connecting to a Voltage Source 125
Connecting a Potentiometer 125
Selecting the Potentiometer Value 126
8 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
Analog Deadband Adjustment 127
Power-On S afet y 128
Under Voltage Safety 128
Data Logging in Analog Mode 128
SECTION 13 Serial (RS-232) Controls and Operation 131
Use and benefits of RS232 131
Connector I/O Pin Assignment (RS232 Mode) 132
Cable configuration 133
Extending the RS232 Cable 133
Communication Settings 134
Establishing Manual Communication with a PC 134
RS232 Communication with the Encoder Module 135
Entering RS232 from R/C or Analog mode 136
Data Logging String in R/C or Analog mode 136
RS232 Mode if default 137
Commands Acknowledge and Error Messages 137
Character Echo 137
Command Acknowledgement 137
Command Error 137
Watchdog time-out 137
RS-232 Watchdog 138
Controller Commands and Queries 138
Set Motor Command Value 139
Set Accessory Output 139
Query Power Applied to Motors 140
Query Amps from Battery to each Motor Channel 140
Query Analog Inputs 140
Query Heatsink Temperatures 141
Query Battery Voltages 141
Query Digital Inputs 142
Reset Controller 142
Accessing & Changing Configuration Parameter in Flash 143
Apply Parameter Changes 143
Flash Configuration Parameters List 144
Input Control Mode 145
Motor Control Mode 145
Amps Limit 146
Acceleration 147
Input Switches Function 147
RC Joystick or Analog Deadband 148
Exponentiation on Channel 1 and Channel 2 148
Left/Right Adjust 149
Default Encoder Time Base 1 and 2 149
Default Encoder Distance Divider 150
AX2550 Motor Controller User’s Manual 9
Default PID Gains 150
Joystick Min, Max and Center Values 150
Reading & Changing Operating Parameters at Runtime 151
Operating Modes Registers 152
Read/Change PID Values 152
PWM Frequency Register 153
Controller Status Register 153
Controller Identification Register 154
Current Amps Limit Registers 154
RS232 Encoder Command Set 155
Read Encoder Counter 155
Set/Reset Encoder Counters and Destination Registers 155
Read Speed 156
Read Distance 157
Read Speed/Distance 157
Read Encoder Limit Switch Status 157
Read / Modify Encoder Module Registers and Parameters 158
Register Description 160
Encoder Hardware ID code 160
Switch Status 160
Speed or Distance 1 or 2 160
Counter Read/Write Mailbox 161
Counter 1 and 2 161
Destination Register 1 and 2 161
Distance 1 and 2 162
Speed 1 and 2 162
Time Base 1 and 2 162
Encoder Threshold 162
Distance Divider 162
Counter Read Data Format 163
Encoder Testing and Setting Using the PC Utility 163
Automatic Switching from RS232 to RC Mode 165
Analog and R/C Modes Data Logging String Format 166
Data Logging Cables 166
Decimal to Hexadecimal Conversion Table 167
SECTION 14 Configuring the Controller using the Switches 171
Programming Methods 171
Programming using built-in Switches and Display 171
Entering Programming Mode 172
Changing parameters 173
The Special Case of Joystick Calibration 173
Restoring factory defaults 173
Exiting the Parameter Setting Mode 174
Programmable Parameters List 174
10 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
SECTION 15 Using the Roborun Configuration Utility 177
System Requirements 177
Downloading and Installing the Utility 177
Connecting the Controller to the PC 178
Roborun Frame, Tab and Menu Descriptions 179
Getting On-Screen Help 180
Loading, Changing Controller Parameters 181
Control Settings 181
Power Settings 182
Analog or R/C Specific Settings 183
Closed Loop Parameters 184
Encoder Setting and Testing 184
Encoder Module Parameters Setting 185
Exercising the Motors 186
Viewing Encoder Data 186
Running the Motors 186
Logging Data to Disk 189
Connecting a Joystick 190
Using the Console 191
Viewing and Logging Data in Analog and R/C Modes 192
Loading and Saving Profiles to Disk 192
Operating the AX2550 over a Wired or Wireless LAN 193
Updating the Controller’s Software 194
Updating the Encoder Software 195
Creating Customized Object Files 195
SECTION 16 Mechanical Specifications 197
Mechanical Dimensions 197
Mounting Considerations 198
Thermal Considerations 199
Attaching the Controller Directly to a Chassis 199
Wire Dimensions 199
Weight 200
AX2550 Motor Controller User’s Manual 11
12 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
SECTION 1 Important Safety
Warnings
Read this Section First
The AX2550 is a high power electronics device. Serious damage, including fire,
may occur to the unit, motors, wiring and batteries as a result of its misuse.
Please review the User’s Manual for added precautions prior to applying full
battery or full load power.
This product is intended for use with rechargeable batteries
Unless special precautions are taken, damage to the controller and/or power supply
may occur if operated with a power supply alone. See“Power Regeneration Considerations” on page 37 of the Users Manual. Always keep the controller connected
to the Battery. Use the Power Control input to turn On/Off.
Do not Connect to a RC Radio with a Battery Attached
Without proper protection, a battery attached to an RC Radio may inject its voltage
directly inside the controller’s sensitive electronics. See
Beware of Motor Runaway in Improperly Closed Loop
Wiring or polarity errors between the feedback device and motor in position or
closed loop position mode may cause the controller to runaway with no possibility
to stop it until power is turned off.
AX2550 Motor Controller User’s Manual 13
Important Safety Warnings
14 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
SECTION 2 AX2550
Quick Start
This section will give you the basic information needed to quickly install, setup and
run your AX2550 controller in a minimal configuration. The AX2850 is a version of
the AX2550 controller with the addition of Optical Encoder inputs.
What you will need
For a minimal installation, gather the following components:
• One AX2550 Controller and its provided cables
• 12V to 40V high capacity, high current battery
• One or two brushed DC motors
• One R/C to DB15 connector (provided)
• Miscellaneous wires, connectors, fuses and switch
Locating the Switches, Wires and Connectors
Take a moment to familiarize yourself with the controller’s wires, switches and con-
nectors.
AX2550 Motor Controller User’s Manual 15
AX2550 Quick Start
The front side (shown in Figure 1) contains the buttons and display needed to operate and
monitor the controller. The 15-pin connector provides the connection to the R/C radio, joystick or microcomputer, as well as connections to optional switches and sensors.
Program Set
Controller Configuration buttons
Connector to
Optical Encoders
(AX2850 only)
FIGURE 1. Front Controller Layout
At the back of the controller (shown in the figure below) are located all the wires that must
be connected to the batteries and the motors.
Controller Power
Power Control
Yellow
Reset
Operating Status
and Program LED
Display
Ground (-)
Black
Connector to Receiver/Controls
and sensors
(top)
Motor (+)
White
Motor (-)
Green
Motor 1
12 to 40V (+)
Red
Ground (-)
Black
12 to 40V (+)
Red
Motor 2
Motor(+)
Yellow or
White
Motor (-)
Green
FIGURE 2. Rear Controller Layout
16 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
Connecting to the Batteries and Motors
Connecting to the Batteries and Motors
Connection to the batteries and motors is shown in the figure below and is done by connecting the set of wires coming out from the back of the controller.
Motor2
Motor1
Power switch
+
-
+
-
VMot
M1-
M1+
PwrCtrl
Controller
GND
GND
GND
M2-
M2+
VMot
Optional
Diode
On
Off
Optional
Emergency
Disconnect
12V to 24V
Motor Battery
Fuse
Notes:
- The Battery Power connection are doubled in order to provide the maximum current to the controller. If
only one motor is used, only one set of motor power cables needs to be connected.
- Typically, 1, 2 or 3 x 12V batteries are connected in series to reach 12, 24 or 36V respectively.
- The Power Control wire MUST be used to turn On and Off the controller.
FIGURE 3. AX2550 Electrical Power Wiring Diagram
1- Connect each motor to one of the two M+ and M- cables pairs. Make sure to respect
the polarity, otherwise the motor(s) may spin in the opposite direction than expected
2- Connect the two thick black wires to the minus (-) terminal of the battery that will be
used to power the motors. Connect the two thick red wires the two VMot terminals to the
plus (+) terminal of the battery. The motor battery may be of 12 to 40 Volts. There is no
need to insert a separate switch on Power cables, although one is suggested for Emergency disconnect. See “Controller Power” on page 30 for a detailed discussion and more
wiring options.
Avoid extending the length of wires from the battery to the controller as the added inductance may cause damage to the controller when operating at high currents. Try extending
the motor wires instead since the added inductance on the motor side of the controller is
not harmful.
The two red wires are connected to each other inside the controller. The same is true
for the black wires. You should wire each pair together as shown in the diagram
above.
3- The yellow Power Control wire and the thin black wire MUST be connected to Ground to
turn the Controller Off. For turning the controller On, even though the Power Control may
be left floating, whenever possible pull it to an unfused12V or higher voltage to keep the
controller logic solidly On. You may use a separate battery to keep the controller alive as
the main Motor battery discharges. Refer to the chapter “Connecting Power and Motors to
AX2550 Motor Controller User’s Manual 17
AX2550 Quick Start
the Controller” on page 29 for more information about batteries and other connection
options.
Important Warning
Do not rely on cutting power to the controller for it to turn off if the Power Control is
left floating. If motors are spinning because the robot is pushed are pushed or
because of inertia, they will act as generators and will turn the controller, possibly in
an unsafe state. ALWAYS ground the Power Control wire to turn the controller Off
and keep it Off.
Important Warning
The controller includes large capacitors. When connecting the Motor Power Cables,
a spark will be generated at the connection point. This is a normal occurrence and
should be expected.
Connecting to the 15-pin Connector
The controller’s I/O are located on it’s standard 15-pin D-Sub Connector. The functions of
some pins varies depending on controller model and operating mode. Pin assignment is
found in the table below.
Signal
Pin
1 2A Digital Output C (same as pin 9)
2TxData
3 RC Ch1 RxData Unused
4 RC Ch 2 Digital Input F
5 Ground Out
6 Ground In
7 +5V In
8 Digital Input E (Not available when Encoder module is present)
9 2A Digital Output C (same as pin 1)
10 Analog Input 2
11 Analog Input 1
12 Analog Input 3 (on RevB hardware)
13 Ground Out
14 +5V Out (100mA max.)
15 Emergency Stop or Invert Switch input
RC Mode RS232 Mode Analog Mode
(Unused on RevB Hardware)
(Unused on RevB Hardware)
and Analog Input 4 (on RevB hardware only)
18 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
Connecting the R/C Radio
Connecting the R/C Radio
Connect the R/C adapter cables to the controller on one side and to two or three channels
on the R/C receiver on the other side. If present, the third channel is for activating the
accessory outputs and is optional.
When operating the controller in “Separate” mode, the wire labelled Ch1 controls Motor1,
and the wire labelled Ch2 controls Motor2.
When operating the controller in “Mixed” mode, Ch1 is used to set the robot’s speed and
direction, while Ch2 is used for steering.
See “R/C Operation” on page 109 of the User’s Manual for a more complete discussion on
R/C commands, calibration and other options.
Channel 3
Channel 2
Channel 1
Pin 1
15
FIGURE 4. R/C connector wiring for 3 channels and battery elimination (BEC)
This wiring - with the wire loop uncut - assumes that the R/C radio will be powered by the
AX2550 controller. Other wiring options are described in “R/C Operation” on page 109 of
the User’s Manual.
Important Warning
Do not connect a battery to the radio when the wire loop is uncut. The RC battery
voltage will flow directly into the controller and cause permanent damage if its voltage is higher than 5.5V.
3: Channel 1 Command Pulses
4: Channel 2 Command Pulses
6: Radio battery (-) Ground
7: Radio battery (+)
8: Channel 3 Command Pulses
8
9
Wire loop bringing power from
controller to RC radio
Connecting the optional channel 3 will enable you to turn on and off the accessory output.
See “Connecting Sensors and Actuators to Input/Outputs” on page 55 and “Activating the
Accessory Outputs” on page 120 of the User’s Manual.
AX2550 Motor Controller User’s Manual 19
AX2550 Quick Start
Powering On the Controller
Important reminder: There is no On-Off switch on the controller. You must insert a switch
on the controller’s power wire as described in section“Connecting to the Batteries and
Motors” on page 17.
To power the controller, center the joystick and trims on the R/C transmitter. In Analog
mode, center the command potentiomenter or joystick.Then turn on the switch that you
have placed on the on the Power Control input.
If the R/C transmitter and/or receiver is powered off, the display on the controller will alternate the letters spelling “no ctrl” to indicate that it is On but is not receiving a control signal.
FIGURE 5. “no control” scroll message indicates no valid R/C signal is present
Turn the R/C transmitter On. The “no ctrl” scrolling message will disappear and the display
will show steady patterns depending on the motor’s selected direction.
Move the joystick on the transmitter to activate the motors to the desired speed and direction.
See “R/C Operation” on page 109 of the User’s Manual for a detailed description of the
many features and options available in the R/C mode.
Button Operation
The AX2550 has three buttons: Set, Program and Reset. These buttons are not needed
for normal operation, as the controller is immediately operational upon power up.
The Reset button will restart the controller. This button is recessed and you will need a
paper clip to press it. Reset is also accomplished by turning the controller’s power Off and
back On.
The Set and Program buttons have the following functions depending how and when they
are pressed:
TABLE 1. AX2550 Buttons Function
Prog and Set button status Function
Press and hold Program alone during reset or power up Enter the Programming Mode.
Press and hold Set alone during reset of power up Enter Self-Test mode. See “Self-Test
Mode” on page 53 of the User’s Manual
Press and hold Program and Set together during reset or
power up
Reset configuration parameters to factory
default
20 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
Default Controller Configuration
TABLE 1. AX2550 Buttons Function
Prog and Set button status Function
Press Program while Programming Mode Accept previous parameter change and
select next parameter
Press Set while in Programming mode Change value of selected parameter
Press Program pressed alone during normal operation No effect
Press Set alone during normal operation No effect
Press Program and Set together during normal operation Emergency stop
Default Controller Configuration
Version 1.9b of the AX2550 software is configured with the factory defaults shown in the
table below. Although Roboteq strives to keep the same parameters and values from one
version to the next, changes may occur from one revision to the next. Make sure that you
have the matching manual and software versions. These may be retrieved from the
Roboteq web site. See “Configuring the Controller using the Switches” on page 171 of the
User Manual for a complete configuration parameter list and their possible values.
TABLE 2. AX2550 Default Settings
Parameter Default Values Letter
Input Command mode: (0) = R/C Radio mode I
Motor Control mode (0) = Separate A, B, speed control, open loop C
Amp limit (5) = 105A A
Acceleration (2) = medium-slow S
Input switch function (3) = no action U
Joystick Deadband (2) = 16% d
Exponentiation on channel 1 (0) = Linear (no exponentiation) E
Exponentiation on channel 2 (0) = Linear (no exponentiation) F
Left / Right Adjust (7) = no adjustment L
Any one of the parameters listed in Table 2, and others not listed, can easily be changed
either using the controller’s buttons or the PC with the Roboteq Configuration Utility. See
“Using the Roborun Configuration Utility” on page 177.
The example below shows how to use the buttons to select and change the Motor Control
mode from “separate” to “mixed”. See “Configuring the Controller using the Switches” on
page 171 of the User’s Manual for a complete list of all the AX2550’s parameters and their
meanings.
AX2550 Motor Controller User’s Manual 21
AX2550 Quick Start
Press & hold Prog
Program mode entered
Press Prog to select
Press Set to select
next value for parameter
Press Prog to store change
and select next parameter
Restart
after 10 seconds
next parameter
Reset controller
to exit
Press and hold the Prog button for 10 seconds while
resetting or powering on the controller
After 10 seconds, the controller will enter the programming mode and flash alternatively the current parameter (I= Input Mode) and its value (0= R/C mode).
Press the Prog button to move to the next parameter
(C= Motor Control Mode) and its value (0= Separate)
Press the Set button to change the parameter’s value
(1= Combined)
Press the Prog button record the change and move to
the next parameter (A= Amps limit) and it’s value (2=
75A)
Press the Reset button or power off/on the control to
restart the controller using the new parameters.
Connecting the controller to your PC using Roborun
Connecting the controller to your PC is not necessary for basic R/C operation. However, it
is a very simple procedure that is useful for the following purposes:
• to Read and Set the programmable parameters with a user-friendly graphical inter-
face
• to obtain the controller’s software revision and date
• to send precise commands to the motors
• to read and plot real-time current consumption value
• Save captured parameters onto disk for later analysis
• to update the controller’s software
22 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
Obtaining the Controller’s Software Revision Number
FIGURE 6. Roborun Utility screen layout
To connect the controller to your PC, use the provided cable. Connect the 15-pin connector
to the controller. Connect the 9-pin connector to your PC’s available port (typically COM1) -
use a USB to serial adapter if needed. Apply power to the controller to turn it on.
Load your CD or download the latest revision of Roborun software from
www.Roboteq.com, install it on your PC and launch the program. The software will automatically establish communication with the controller, retrieve the software revision number and present a series of buttons and tabs to enable its various possibilities.
The intuitive Graphical User Interface will let you view and change any of the controller’s
parameters. The “Run” tab will present a number of buttons, dials and charts that are used
for operating and monitoring the motors.
Obtaining the Controller’s Software Revision Number
One of the unique features of the AX2550 is the ability to easily update the controller’s
operating software with new revisions downloaded from Roboteq’s web site at
www.roboteq.com. This is useful for adding features and/or improving existing ones.
Each software version is identified with a unique number. Obtaining this number can be
done using the PC connection discussed previously.
AX2550 Motor Controller User’s Manual 23
AX2550 Quick Start
FIGURE 7. Press and hold “Set” to display version number and enter self-test
It is also possible to get the controller to display the software version number by following
these simple steps
• Disconnect the power from the motor batteries. Power the controller only via the
Power Control input.
• Press and hold the Set button while powering or resetting the controller.
The LED will display a sequence of two numerical digits and an optional letter separated by
dashes as shown in the examples below.
= Software version 1.9b
After these digits are displayed, the controller will attempt to power the motors as part of
the self test mode (see “Self-Test Mode” on page 53 of the User’s Manual for a more
detailed explanation). This is why the motor’s battery must be disconnected. After about
30 seconds, the software revision number will be displayed again the cycle will repeat.
You will need to reset, or power down and up, the controller to exit and resume normal
operation.
Now that you know your controller’s software version number, you will be able to see if a
new version is available for download and installation from Roboteq’s web site and which
features have been added or improved.
Installing new software is a simple and secure procedure, fully described in “Updating the
Controller’s Software” on page 194 of the User’s Manual.
Exploring further
By following this quick-start section, you should have managed to get your controller to
operate in its basic modes within minutes of unpacking.
Each of the features mentioned thus far has numerous options which are discussed further
in the complete User’s Manual, including:
• Self test mode
• Emergency stop condition
• Joystick calibration
• Using Inputs/Outputs
• Current limiting
• Closed Loop Operation
• Software updating
• and much more
24 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
SECTION 3 AX2550 Motor
Controller
Overview
Congratulations! By selecting Roboteq’s AX2550 you have empowered yourself
with the industry’s most versatile, powerful and programmable DC Motor Controller
for mobile robots. This manual will guide you step by step through its many possibilities.
Product Description
The AX2550 is a highly configurable, microcomputer-based, dual-channel digital
speed or position controller with built-in high power drivers. The controller is
designed to interface directly to high power DC motors in computer controlled or
remote controlled mobile robotics and automated vehicle applications.
The AX2550 controller can accept speed or position commands in a variety of ways:
pulse-width based control from a standard Radio Control receiver, Analog Voltage
commands, or RS-232 commands from a microcontroller or wireless modem.
The controller's two channels can be operated independently or can be combined to
set the forward/reverse direction and steering of a vehicle by coordinating the
motion on each side of the vehicle. In the speed control mode, the AX2550 can
operate in open loop or closed loop. In closed loop operation, actual speed measurements from tachometers or optical encoders are used to verify that the motor is
rotating at the desired speed and direction and to adjust the power to the motors
accordingly.
The AX2550 can also be configured to operate as a precision, high torque servo controller. When connected to a potentiometer coupled to the motor assembly, the
controller will command the motor to rotate up to a desired angular position.
Depending on the DC motor's power and gear ratio, the AX2550 can be used to
move or rotate steering columns or other physical objects with very high torque.
The AX2550 is fitted with many safety features ensuring a secure power-on start,
automatic stop in case of command loss, over current protection on both channels,
and overheat protection.
AX2550 Motor Controller User’s Manual 25
AX2550 Motor Controller Overview
The motors are driven using high-efficiency Power MOSFET transistors controlled using
Pulse Width Modulation (PWM) at 16kHz. The AX2550 power stages can operate from 12
to 40VDC and can sustain up to 120A of controlled current, delivering up to 4,800W
(approximately 6 HP) of useful power to each motor.
The many programmable options of the AX2550 are easily configured using the supplied
PC utility or one-touch Program and Set buttons and a 7-segment LED display. Once programmed, the configuration data are stored in the controller's non-volatile memory, eliminating the need for cumbersome and unreliable jumpers.
The AX2850 is the AX2550 controller fitted with a dual channel optical encoder input module. Optical Encoders allow precise motor speed and position measurement and enable
advance robotic applications.
Technical features
Fully Digital, Microcontroller-based Design
• Multiple operating modes
• Fully programmable using either built-in switches and 7 segment display or through
connection to a PC
• Non-volatile storage of user configurable settings
• Simple operation
• Software upgradable with new features
Multiple Command Modes
• Radio-Control Pulse-Width input
• Serial port (RS-232) input
• 0-5V Analog Command input
Multiple Advanced Motor Control Modes
• Independent operation on each channel
• Mixed control (sum and difference) for tank-like steering
• Open Loop or Closed Loop Speed mode
• Position control mode for building high power position servos
• Modes selectable independently for each channel
Automatic Joystick Command Corrections
• Joystick min, max and center calibration
• Selectable deadband width
• Selectable exponentiation factors for each joystick
• 3rd R/C channel input for accessory output activation (disabled when encoder mod-
ule present)
Special Function Inputs/Outputs
• 2 Analog inputs. Used as:
26 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
Technical features
• Tachometer inputs for closed loop speed control
• Potentiometer input for position (servo mode)
• Motor temperature sensor inputs
• External voltage sensors
• User defined purpose (RS232 mode only)
• 2 Extra analog inputs (on RevB hardware). Used as:
• Potentiometer input for position while in analog command mode
• User defined purpose (RS232 mode only)
• One Switch input configurable as
• Emergency stop command
• Reversing commands when running vehicle inverted
• General purpose digital input
• One general purpose 24V, 2A output for accessories
• Up to 2 general purpose digital inputs
Optical Encoder Inputs (AX2850 only)
• Inputs for two Quadrature Optical Encoders
• up to 250khz Encoder frequency per channel
• two 32-bit up-down counters
• Inputs may be shared with four optional limit switches per channel
Internal Sensors
• Voltage sensor for monitoring the main 12 to 40V battery system operation
• Voltage monitoring of internal 12V
• Temperature sensors on the heat sink of each power output stage
• Sensor information readable via RS232 port
Low Power Consumption
• On board DC/DC converter for single 12 to 40V battery system operation
• Optional backup power input for powering safely the controller if the motor batteries
are discharged
• Max 200mA at 12V or 100mA at 24V idle current consumption
• Power Control wire for turning On or Off the controller from external microcomputer
or switch
• No power consumed by output stage when motors are stopped
• Regulated 5V output for powering R/C radio. Eliminates the need for separate R/C
battery
High Efficiency Motor Power Outputs
• Two independent power output stages
• Optional Single Channel operation at double the current
• Dual H bridge for full forward/reverse operation
• Ultra-efficient 2.5mOhm (1.25mOhm on HE version) ON resistance (RDSon) MOS-
FET transistors
• Synchronous Rectification H Bridge
AX2550 Motor Controller User’s Manual 27
AX2550 Motor Controller Overview
• 12 to 40 V operation
• High current 8 AWG cable sets for each power stages
• Temperature-based Automatic Current Limitation
• 120A up to 15 seconds (per channel)
• 100A up to 30 seconds
• 80A extended
• High current operation may be extended with forced cooling
• 250A peak Amps per channel
• 16kHz Pulse Width Modulation (PWM) output
• Auxiliary output for brake, clutch or armature excitation
• Heat sink extruded case
Advanced Safety Features
• Safe power on mode
• Optical isolation on R/C control inputs
• Automatic Power stage off in case of electrically or software induced program fail-
ure
• Overvoltage and Undervoltage protection
• Regeneration current limiting
• Watchdog for automatic motor shutdown in case of command loss (R/C and RS232
modes)
• Large, bright run/failure diagnostics on 7 segment LED display
• Programmable motor acceleration
• Built-in controller overheat sensor
• Emergency Stop input signal and button
Data Logging Capabilities
• 13 internal parameters, including battery voltage, captured R/C command, tempera-
ture and Amps accessible via RS232 port
• Data may be logged in a PC, PDA or microcomputer
Sturdy and Compact Mechanical Design
• Built from aluminum heat sink extrusion with mounting brackets
• Efficient heat sinking. Operates without a fan in most applications.
• 7” (178mm) long (excluding mounting brackets) by 5.5” wide (140mm) by 1.8”
(40mm) high
• -20o to +85o C case operating environment
• 3.3 lbs (1500g)
28 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
Power Connections
SECTION 4 Connecting
Power and
Motors to the
Controller
This section describes the AX2550 Controller’s connections to power sources and motors.
Important Warning
Please follow the instructions in this section very carefully. Any problem due to wiring errors may have very serious consequences and will not be covered by the product’s warranty.
Power Connections
The AX2550 has three Ground (black), two Vmot (red) power cables and a Power Control
wire (yellow). The power cables are located at the back end of the controller. The various
power cables are identified by their position, wire thickness and color: Red is positive (+),
black is negative or ground (-).
The power connections to the batteries and motors are shown in the figure below.
AX2550 Motor Controller User’s Manual 29
Connecting Power and Motors to the Controller
Controller Power
Power Control
Ye l l o w
Motor (+)
White
Motor (-)
Green
12 to 40V (+)
Red
Motor 1
FIGURE 8. Controller rear plate and power wiring
Ground (-)
Black
Ground (-)
Black
12 to 40V (+)
Red
Motor(+)
Ye l l o w o r
Motor 2
(top)
Motor (-)
Green
White
Controller Power
The AX2550 uses a flexible power supply scheme that is best described in Figure 9. In this
diagram, it can be seen that the power for the Controller’s microcomputer is separate from
this of the motor drivers. The microcomputer circuit is connected to a DC/DC converter
which takes power from either the Power Control wire or the VMot input. The diode circuit
is designed to automatically select one power source over the other, letting through the
source that is higher than the other.
30 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007
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