Copley Controls Corp. XTL, Xenus XTL User Manual
Xenus XTL™ User Guide
P/N 95-00875-000
Revision 3
June 2008
Xenus XTL User Guide
This page for notes.
TABLE OF CONTENTS
About This Manual ................................................................................................................................................................................5
1: Introduction ................................................................................................................................................................................. 9
1.1: Amplifier ............................................................................................................................................................................... 10
1.2: CME 2 .................................................................................................................................................................................. 11
1.3: CMO/CML ............................................................................................................................................................................11
2: Operational Theory....................................................................................................................................................................13
2.1: Amplifier Internal Power........................................................................................................................................................ 14
2.2: Synchronizing PWM Switching Frequency............................................................................................................................ 16
2.3: Commutation Modes ............................................................................................................................................................ 16
2.4: Feedback.............................................................................................................................................................................. 16
2.5: Operating Modes.................................................................................................................................................................. 17
2.6: CANopen Operation .............................................................................................................................................................28
2.7: Limit Switches ...................................................................................................................................................................... 30
2.8: Brake Operation ................................................................................................................................................................... 31
2.9: Status Indicators................................................................................................................................................................... 32
2.10: Protection...........................................................................................................................................................................34
2.11: Position and Velocity Errors................................................................................................................................................ 36
2.12: Communication ..................................................................................................................................................................39
2.13: Inputs .................................................................................................................................................................................40
2.14: Outputs............................................................................................................................................................................... 41
2.15: Regen Resistor Theory....................................................................................................................................................... 42
3: Specifications............................................................................................................................................................................ 43
3.1: Agency Approvals.................................................................................................................................................................44
3.2: Power Input ..........................................................................................................................................................................44
3.3: Power Output........................................................................................................................................................................ 44
3.4: Control Loops ....................................................................................................................................................................... 45
3.5: Regen Circuit Output ............................................................................................................................................................ 45
3.6: Digital Command Input ......................................................................................................................................................... 45
3.7: Analog Command Input........................................................................................................................................................46
3.8: Digital Inputs.........................................................................................................................................................................46
3.9: Digital Outputs......................................................................................................................................................................46
3.10: Brake Output ...................................................................................................................................................................... 47
3.11: Encoder Power Supply Output............................................................................................................................................ 47
3.12: Primary Encoder Inputs ...................................................................................................................................................... 47
3.13: Analog Encoder Inputs .......................................................................................................................................................47
3.14: Hall Switch Inputs...............................................................................................................................................................48
3.15: Resolver Interface .............................................................................................................................................................. 48
3.16: Multi-Mode Port .................................................................................................................................................................. 48
3.17: Serial Interface ................................................................................................................................................................... 49
3.18: CAN Interface.....................................................................................................................................................................49
3.19: Status Indicators................................................................................................................................................................. 49
3.20: Fault Levels ........................................................................................................................................................................ 49
3.21: Power Dissipation............................................................................................................................................................... 50
3.22: Thermal Impedance............................................................................................................................................................50
3.23: Mechanical and Environmental...........................................................................................................................................50
3.24: Dimensions......................................................................................................................................................................... 51
4: Wiring......................................................................................................................................................................................... 53
4.1: General Wiring Instructions ..................................................................................................................................................54
4.2: AC Mains (J1)....................................................................................................................................................................... 56
4.3: Motor (J2) ............................................................................................................................................................................. 57
4.4: Regen Resistor (J3) (Optional) .............................................................................................................................................59
4.5: Logic Supply / Brake (J4)...................................................................................................................................................... 60
4.6: RS-232 Serial Communications (J5)..................................................................................................................................... 61
4.7: CAN Bus (J6) ....................................................................................................................................................................... 62
4.8: Control (J7)........................................................................................................................................................................... 63
4.9: Motor Feedback (J8)............................................................................................................................................................. 67
5: Quick Setup with CME 2 ........................................................................................................................................................... 73
5.1: Warnings..............................................................................................................................................................................74
5.2: CME 2 Installation and Serial Port Setup.............................................................................................................................. 75
5.3: Prerequisites ........................................................................................................................................................................ 79
5.4: Basic Setup..........................................................................................................................................................................81
5.5: Motor/Feedback Setup .........................................................................................................................................................84
5.6: Amplifier Configuration .........................................................................................................................................................93
5.7: Command Input.................................................................................................................................................................. 103
5.8: Auto Phase.........................................................................................................................................................................110
5.9: Current Loop....................................................................................................................................................................... 116
5.10: Velocity Loop....................................................................................................................................................................120
5.11: Position Loop.................................................................................................................................................................... 122
5.12: Completion Steps .............................................................................................................................................................126
6: Using CME 2 ............................................................................................................................................................................ 127
Copley Controls Corp. 3
Table of Contents Xenus XTL User Guide
6.1: CME 2 Overview.................................................................................................................................................................128
6.2: Manage Amplifier and Motor Data ...................................................................................................................................... 133
6.3: Downloading Firmware .......................................................................................................................................................136
6.4: Control Panel...................................................................................................................................................................... 138
6.5: Manual Phasing.................................................................................................................................................................. 142
6.6: Home Function................................................................................................................................................................... 144
A: Regen Resistor Sizing and Configuration ............................................................................................................................. 145
A.1: Sizing a Regen Resistor..................................................................................................................................................... 146
A.2: Configuring a Custom Regen Resistor ............................................................................................................................... 150
B: I2T Time Limit Algorithm ......................................................................................................................................................... 153
B.1: I2T Algorithm ...................................................................................................................................................................... 154
C: Thermal Considerations.......................................................................................................................................................... 159
C.1: Operating Temperature and Cooling Configurations .......................................................................................................... 160
C.2: Heatsink Mounting Instructions .......................................................................................................................................... 162
D: Xenus Filter.............................................................................................................................................................................. 163
D.1: Overview............................................................................................................................................................................164
D.2: XTL-FA-01 Edge Filter Specifications ................................................................................................................................ 165
D.3: Thermal Considerations..................................................................................................................................................... 165
D.4: XTL-FA-01 Edge Filter Dimensions.................................................................................................................................... 166
D.5: XTL-FA-01 Edge Filter Wiring............................................................................................................................................ 167
D.6: XTL-FA-01 Edge Filter Ordering.........................................................................................................................................171
E: Connecting for Serial Control................................................................................................................................................. 173
E.1: Single-Axis and Multi-Drop ................................................................................................................................................. 174
F: Ordering Guide and Accessories ........................................................................................................................................... 175
F.1: Amplifier Model Numbers ................................................................................................................................................... 176
F.2: Accessory Model Numbers.................................................................................................................................................177
F.3: Order Example ................................................................................................................................................................... 178
F.5: Copley Standard Regen Resistor Specifications................................................................................................................. 179
4 Copley Controls Corp.
ABOUT THIS MANUAL
Overview and Scope
This manual describes the operation and installation of the Xenus XTL amplifier manufactured by
Copley Controls Corporation.
Related Documentation
For important setup and operation information, see the CME 2 User Guide.
Users of the CANopen features should also read these Copley Controls documents:
• CANopen Programmer’s Manual
• CML Reference Manual
• Copley Motion Objects Programmer’s Guide
Also of related interest:
• Copley Indexer 2 Program User’s Guide (describes use of Indexer Program to create motion
control sequences)
• Copley Controls ASCII Interface Programmer’s Guide (describes how to send ASCII format
commands over an amplifier’s serial bus to set up and control one or more amplifiers)
• Copley Amplifier Parameter Dictionary
• Copley Camming User Guide
• Copley DeviceNet Programmer’s Guide
Information on Copley Controls Software can be found at:
http://www.copleycontrols.com/Motion/Products/Software/index.html
Comments
Copley Controls Corporation welcomes your comments on this manual.
For contact information, see http://www.copleycontrols.com
Copyrights
No part of this document may be reproduced in any form or by any means, electronic or
mechanical, including photocopying, without express written permission of Copley Controls
Corporation.
Xenus and XTL are registered trademarks of Copley Controls Corporation.
CME 2 is a registered trademark of Copley Controls Corporation.
Windows NT, ME, 2000, XP, Vista, Visual Basic, Excel, and .NET are trademarks or registered
trademarks of the Microsoft Corporation.
LabVIEW is a registered trademark of National Instruments.
Document Validity
We reserve the right to modify our products. The information in this document is subject to change
without notice and does not represent a commitment by Copley Controls Corporation. Copley
Controls Corporation assumes no responsibility for any errors that may appear in this document.
Copley Controls Corp. 5
About this Manual Xenus XTL User Guide
Product Warnings
Observe all relevant state, regional, and local safety regulations when installing and using this
product. For safety and to assure compliance with documented system data, only Copley Controls
Corporation should perform repairs to amplifiers.
DANGER: Hazardous voltages.
Exercise caution when installing and adjusting.
!
DANGER
!
DANGER
!
DANGER
Failure to heed this warning can cause equipment damage, injury, or death.
Risk of electric shock.
High-voltage circuits on J1, J2, and J3 are connected to mains power.
Failure to heed this warning can cause equipment damage, injury, or death.
Risk of unexpected motion with non-latched faults.
After the cause of a non-latched fault is corrected, the amplifier re-enables the PWM
output stage without operator intervention. In this case, motion may re-start
unexpectedly. Configure faults as latched unless a specific situation calls for nonlatched behavior. When using non-latched faults, be sure to safeguard against
unexpected motion.
Failure to heed this warning can cause equipment damage, injury, or death.
Using CME 2 or serial commands may affect or suspend CAN operations.
When operating the amplifier as a CAN node, the use of CME 2 or ASCII serial
!
DANGER
!
DANGER
!
DANGER
commands may affect CAN operations in progress. Using such commands to initiate
motion may cause CAN operations to suspend.
CAN operations may restart unexpectedly when the commanded motion is stopped.
Failure to heed this warning can cause equipment damage, injury, or death.
Latching an output does not eliminate the risk of unexpected motion with nonlatched faults.
Associating a fault with a latched, custom-configured output does not latch the fault
itself. After the cause of a non-latched fault is corrected, the amplifier re-enables
without operator intervention. In this case, motion may re-start unexpectedly.
For more information, see Clearing Non-Latched Faults (p. 34).
Failure to heed this warning can cause equipment damage, injury, or death.
Use equipment as described.
Operate amplifiers within the specifications provided in this manual.
Failure to heed this warning can cause equipment damage, injury, or death.
6 Copley Controls Corp.
Xenus XTL User Guide About this Manual
Revision History
Revision Date DECO# Comments
1 December 2007 16236 Initial release.
2 February 2008 16714 Updated Multi-Mode Port Interface Diagram (p. 66).
3 June 2008 17111 Updated Web page references and made other minor changes.
Copley Controls Corp. 7
About this Manual Xenus XTL User Guide
This page for notes.
8 Copley Controls Corp.
CHAPTER
1: INTRODUCTION
This chapter provides an overview of the Copley Controls Xenus XTL amplifier.
Contents include:
Title Page
1.1: Amplifier ............................................................................................................................................................................... 10
1.2: CME 2 .................................................................................................................................................................................. 11
1.3: CMO/CML ............................................................................................................................................................................11
Copley Controls Corp. 9
Introduction Xenus XTL User Guide
1.1: Amplifier
Xenus provides 100% digital control of brushless or brush motors in an off-line powered package.
It can also control a Copley Controls ServoTube motor. Xenus can operate from single or threephase mains with a continuous power output of up to 4 kW.
Xenus is offered in three versions to support three types of feedback devices. The standard
version supports digital quadrature encoders. The –S version supports analog sin/cos encoders.
The -R version supports brushless resolvers. The –S and -R versions can emulate a digital
quadrature encoder output from the analog encoder or resolver respectively.
Xenus can operate in several basic ways:
• As a traditional motor amplifier accepting current, velocity or position commands from an
external controller. In current and velocity modes it can accept ±10 Vdc analog, digital 50%
PWM or PWM/polarity inputs. In position mode, inputs can be incremental position commands
from step-motor controllers in Pulse and Direction or Count Up/Count Down format, as well as
A/B quadrature commands from a master-encoder. Pulse-to-position ratio is programmable for
electronic gearing.
• As a node on a CANopen network. CANopen compliance allows the amplifier to take
instruction from a master application over a CAN network to perform torque, velocity, and
position profiling, interpolated motion, and homing operations. Multiple drives can be tightly
synchronized for high performance coordinated motion.
• As a node on a DeviceNet network. Xenus can be operated over a DeviceNet network by
PLCs and other controllers.
• As a stand-alone controller running Copley Virtual Machine (CVM) control programs such as
the Indexer 2 Program. It can also be controlled directly over an RS232 serial link with simple
ASCII format commands.
Mains input voltage to the amplifier can range from 100 to 240 Vac, single or three-phase, and 47
to 63 Hz. This allows Xenus the ability to work in the widest possible range of industrial settings.
Several models are available, with peak current ratings of 18 to 40 amps:
Model
Quad A/B
Encoder
XTL-230-18 XTL-230-18-R XTL-230-18-S 6 A 18 A
XTL-230-36 XTL-230-36-R XTL-230-36-S 12 A 36 A
XTL-230-40 XTL-230-40-R XTL-230-40-S 20 A 40 A
Resolver Sin/Cos Encoder Continuous
Current
Peak Current Vac
100 to
240
A separate +24 Vdc logic supply powers the internal logic and control circuits. These are isolated
from the high-voltage power supply and inverter stage that connect to the mains. This simplifies
system design by allowing the mains to be completely disconnected from the amplifier for safety
reasons while allowing the logic side of the amplifier to stay powered. This allows the amplifier to
retain position information and maintain communication through the digital I/O or over the serial or
CAN ports when disconnected from the mains.
The Xenus XTL is RoHS compliant.
10 Copley Controls Corp.
Xenus XTL User Guide Introduction
1.2: CME 2
Amplifier commissioning is fast and simple using Copley Controls CME 2 software. CME 2
communicates with Xenus via an RS-232 link, and all of the operations needed to configure the
amplifier are accessible through CME 2.
The multi-drop feature allows CME 2 to use a single RS-232 serial connection to one amplifier as
a gateway to other amplifiers linked together by CAN bus connections.
Auto phasing of brushless motor Hall sensors and phase wires eliminates “wire and try.”
Connections are made once and CME 2 does the rest. Encoder or resolver wire swapping to
establish the direction of positive motion is also eliminated.
Motor data can be saved as .ccm files. Amplifier data is saved as .ccx files that contain all
amplifier settings plus motor data. This makes it possible to quickly set up amplifiers by copying
configurations from one amplifier to another.
1.3: CMO/CML
Copley Motion Libraries (CML) and Copley Motion Objects (CMO) make CANopen system
commissioning fast and simple. All network housekeeping is taken care of automatically by a few
simple commands linked into your application program. CML provides a suite of C++ libraries,
allowing a C++ application program to communicate with and control an amplifier over the
CANopen network. CMO provides a similar suite of COM objects that can be used by Visual
Basic, .NET, LabVIEW, or any other program supporting the Microsoft COM object interface.
Copley Controls Corp. 11
Introduction Xenus XTL User Guide
12 Copley Controls Corp.
CHAPTER
2: OPERATIONAL THEORY
This chapter describes the basics of Xenus operation. Contents include:
Title Page
2.1: Amplifier Internal Power........................................................................................................................................................ 14
2.2: Synchronizing PWM Switching Frequency............................................................................................................................ 16
2.3: Commutation Modes ............................................................................................................................................................ 16
2.4: Feedback.............................................................................................................................................................................. 16
2.5: Operating Modes.................................................................................................................................................................. 17
2.6: CANopen Operation .............................................................................................................................................................28
2.7: Limit Switches ...................................................................................................................................................................... 30
2.8: Brake Operation ................................................................................................................................................................... 31
2.9: Status Indicators................................................................................................................................................................... 32
2.10: Protection...........................................................................................................................................................................34
2.11: Position and Velocity Errors................................................................................................................................................ 36
2.12: Communication ..................................................................................................................................................................39
2.13: Inputs .................................................................................................................................................................................40
2.14: Outputs............................................................................................................................................................................... 41
2.15: Regen Resistor Theory....................................................................................................................................................... 42
Copley Controls Corp. 13
Operational Theory Xenus XTL User Guide
2.1: Amplifier Internal Power
Power distribution within Xenus is divided into three sections: +24 Vdc, logic/signal, and high
voltage. Each is isolated from the other.
2.1.1: Logic/Signal Power
An internal DC/DC converter operates from the +24 Vdc Logic Supply input and creates the
required logic/signal operating voltages, the isolated voltages required for the high-voltage control
circuits, and a +5 Vdc supply for powering the motor encoder and Hall circuits. All the digital and
analog inputs, digital outputs (with the exception of OUT4), Hall and encoder inputs are referenced
to the same signal common. OUT4 is controlled through an opto-isolator, and is referenced to the
+24 Vdc return. The CAN interface is also optically isolated.
Deriving internal operating voltages from a separate source enables the amplifier to stay on-line
when the mains have been disconnected for emergency-stop or operator-intervention conditions.
This allows CAN bus and serial communications to remain active so that the amplifier can be
monitored by the control system while the mains power is removed.
2.1.2: High Voltage
Mains power drives the high-voltage section. It is rectified and capacitor-filtered to produce the DC
bus: the DC “link” power that drives the PWM inverter, where it is converted into the voltages that
drive a three-phase brushless or DC brush motor. An internal solid-state switch, together with an
external power resistor, provides dissipation during regeneration when the mechanical energy of
the motor is converted back into electrical energy. This prevents charging the internal capacitors
to an overvoltage condition.
14 Copley Controls Corp.
Xenus XTL User Guide Operational Theory
2.1.3: Power and Grounding Diagram
SHIELD
AMPLIFIER
CHASSIS
REGEN(-)
REGEN(+)
FRAME
(SAFETY)
GROUND
+24
VDC
+24 Vdc
GROUND
CAN
Network
CONTROL
SYSTEM
MAINS
BRAKE
J1
J4
J6
L1
L2
L3
+24 Vdc
BRAKE
RTN
+5 Vdc
~
~
~
CAN
Bus
Ckt
DC/DC
Cntrl
DC/DC
Converter
+
-
1760 PF
+
J3
PWM
STAGE
CONTROL
POWER
LOGIC
&
SIGNAL
POWER
DC BUSS(+)
INVERTER
DC BUSS(-)
ISOLATION BARRIER
+5 Vdc @
400mA
PWM
SHIELD
+5 Vdc
SIGNAL GND
+5 Vdc
W
J2
U
V
MOTOR
CASE
HALLS
J8
ENCODER
J7
CONTROL
SIGNAL
GROUND
ENABLE [IN1]
SIGNAL GND
CONTROL
LOGIC
SIGNAL GND
Copley Controls Corp. 15
Operational Theory Xenus XTL User Guide
2.2: Synchronizing PWM Switching Frequency
In some situations, such as when sampling small analog signals, it is desirable to synchronize the
PWM switching frequency among multiple amplifiers. In these cases, one amplifier serves as a
master for one or more slave amplifiers. The PWM sync output of the master sends a signal that
is received as a PWM sync input by each slave.
2.3: Commutation Modes
The amplifier supports three commutation modes to drive brush and brushless motors: AC
brushless sinusoidal, AC brushless trapezoidal, and DC brush.
In most applications, sinusoidal commutation is preferred over trapezoidal, because it reduces
torque ripple and offers the smoothest motion at any velocity or torque. In the sinusoidal
commutation mode, an encoder or a resolver are required for all modes of operation.
In AC brushless trapezoidal commutation mode, the amplifier provides traditional six-step
commutation.
When driving a DC brush motor, the amplifier operates as a traditional H-Bridge amplifier.
2.4: Feedback
2.4.1: Encoder and Resolver Support
The Xenus amplifier is offered in three versions to support encoder or resolver feedback. The
standard version supports digital quadrature encoders. The -S version supports analog sin/cos
encoders. These versions normally require the use of Hall switches for the commutation of
brushless motors. The resolver version supports standard, single speed, transmit-type resolvers.
2.4.2: Multi-Mode Port
All versions support a multi-mode port. This interface can be configured to:
• Provide a buffered digital encoder output based on the digital encoder input.
• Provide an emulated digital encoder output based on the analog encoder or resolver input.
• Provide a second digital encoder input to be used in the dual encoder position mode. In this
mode, an encoder attached to the load provides position loop feedback, and the motor
encoder or resolver provides velocity loop feedback.
16 Copley Controls Corp.
Xenus XTL User Guide Operational Theory
2.5: Operating Modes
2.5.1: Modes and Control Loops
Nesting of Control Loops and Modes
Copley Controls amplifiers use up to three nested control loops - current, velocity, and position - to
control a motor in three associated operating modes.
Control Loops Illustration
In position mode, the amplifier uses all three loops. As shown below, the position loop drives the
nested velocity loop, which drives the nested current loop.
Limits
Target
Position
Trajectory
G
enerator
Position
Command
Position
L
oop
Ve loc ity
Command
Velocity
L
imiter
Limited
Velocity
Cur re nt
FILTER
Veloc ity
L
oop
Co mman d
FILTER
Cur re nt
L
Limited
Current
Current
imiter
Ac tual CurrentDerived VelocityActual Position
PWM
Command
L
oop
Motor/
S
ensors
In velocity mode, the velocity loop drives the current loop. In current mode, the current loop is
driven directly by external or internal current commands.
Basic Attributes of All Control Loops
These loops (and servo control loops in general) share several common attributes:
Loop Attribute Description
Command input Every loop is given a value to which it will attempt to control. For example, the velocity loop
receives a velocity command that is the desired motor speed.
Limits Limits are set on each loop to protect the motor and/or mechanical system.
Feedback The nature of servo control loops is that they receive feedback from the device they are
controlling. For example, the position loop uses the actual motor position as feedback.
Gains These are constant values that are used in the mathematical equation of the servo loop. The
values of these gains can be adjusted during amplifier setup to improve the loop
performance. Adjusting these values is often referred to as tuning the loop.
Output The loop generates a control signal. This signal can be used as the command signal to another
control loop or the input to a power amplifier.
Copley Controls Corp. 17
Operational Theory Xenus XTL User Guide
2.5.2: Current Mode and Current Loop
Current Loop Diagram
As shown below, the “front end” of the current loop is a limiting stage. The limiting stage accepts a
current command, applies limits, and passes a limited current command to the summing junction.
The summing junction takes the limited current command, subtracts the actual current
(represented by the feedback signal), and produces an error signal. This error signal is then
processed using the integral and proportional gains to produce a command. This command is
then applied to the amplifier’s power stage.
Current Command
Current Off set
Limits:
Peak Current
Continuous Current
Peak Curr ent Limit Time
Current Lim iter
Limited Current
Current Loop
Current Integral Gain (Ci)
+
-
Current Proportional Gain (Cp)
Feedback (A ctual Current)
+
+
PWM
Comman d
Mot or
Current Loop Inputs
• The amplifier’s analog or PWM inputs.
• A network command, CANopen, DeviceNet, or RS-232 Serial.
• A Copley Virtual Motion (CVM) control program.
• The amplifier’s internal function generator.
In velocity or position modes, the current command is generated by the velocity loop.
Offset
The current loop offset is intended for use in applications where there is a constant force applied
to, or required of, the servomotor and the system must control this force. Typical applications
would be a vertical axis holding against gravity, or web tensioning. This offset value is summed
with the current command before the limiting stage.
Limits
The current command is limited based on the following parameters:
Limiter Description
Peak Current Limit Maximum current that can be generated by the amplifier for a short duration of time. This
value cannot exceed the peak current rating of the amplifier.
Continuous Current
Limit
I2T Time Limit Maximum amount of time that the peak current can be applied to the motor before it must
Ramp Rate of change in current command.
18 Copley Controls Corp.
Maximum current that can be constantly generated by the amplifier.
be reduced to the continuous limit or generate a fault.
For more details, see I
Note: Although the current limits set by the user may exceed the amplifier's internal limits,
the amplifier operates using both sets of limits in parallel, and therefore will not exceed its
own internal limits regardless of the values programmed.
2
T Time Limit Algorithm (p. 153).
Xenus XTL User Guide Operational Theory
Current Loop Gains
The current loop uses these gains:
Gain Description
Cp - Current loop proportional The current error (the difference between the actual and the limited commanded
current) is multiplied by this value. The primary effect of this gain is to increase
bandwidth (or decrease the step-response time) as the gain is increased.
Ci - Current loop integral The integral of the current error is multiplied by this value. Integral gain reduces the
current error to zero over time. It controls the DC accuracy of the loop, or the
flatness of the top of a square wave signal. The error integral is the accumulated
sum of the current error value over time.
Current Loop Output
The output of the current loop is a command that sets the duty cycle of the PWM output stage of
the amplifier.
Auto Tune
CME 2 provides a current loop Auto Tune feature, which automatically determines optimal Cp and
Ci values for the motor. For more information, see Auto Tune the Current Loop (p. 117).
Copley Controls Corp. 19
Operational Theory Xenus XTL User Guide
2.5.3: Velocity Mode and Velocity Loop
Velocity Loop Diagram
As shown below, the velocity loop limiting stage accepts a velocity command, applies limits, and
passes a limited velocity command to the input filter. The filter then passes a velocity command to
the summing junction. The summing junction subtracts the actual velocity, represented by the
feedback signal, and produces an error signal. (The velocity loop feedback signal is always from
the motor feedback device even when an additional encoder is attached to the load.) The error
signal is then processed using the integral and proportional gains to produce a current command.
Programmable digital filters are provided on both the input and output command signals.
Velocity Loop
Velocity
C
ommand
Limits:
*Not used w hen velocity loop is c ontrolled by position loop. See "V elocity Loop Limits" f or details.
Ve lo city L im ite r
Velocity
Acceleration*
Deceleration*
E
mergenc y Stop Deceleration*
Fil te r
Limited
Velocity
+
Feedback (Derived V elocity )
-
Veloc ity Integral Gain (V i)
V
elocity Proportional Gain (V p)
+
+
Filter
Current
Command
Inputs
In velocity mode, the velocity command comes from one of the following:
• The amplifier’s analog or PWM inputs.
• A network command, CANopen, DeviceNet, or RS-232 Serial.
• A Copley Virtual Motion (CVM) control program.
• The amplifier’s internal function generator.
In position mode, the velocity command is generated by the position loop.
Velocity Loop Limits
The velocity command is limited based on the following set of parameters designed to protect the
motor and/or the mechanical system.
Limiter Description
Velocity Limit Sets the maximum velocity command input to the velocity loop.
Acceleration Limit Limits the maximum acceleration rate of the commanded velocity input to the velocity loop.
This limit is used in velocity mode only.
Deceleration Limit Limits the maximum deceleration rate of the commanded velocity input to the velocity loop.
This limit is used in velocity mode only.
Fast Stop Ramp Specifies the deceleration rate used by the velocity loop when the amplifier is hardware
disabled. (Fast stop ramp is not used when amplifier is software disabled.) If the brake
delay option is programmed, the fast stop ramp is used to decelerate the motor before
applying the brake.
Note that Fast Stop Ramp is used only in velocity mode. In position mode, the trajectory
generator handles controlled stopping of the motor. There is one exception: if a non-latched
following error occurs in position mode, then the amplifier drops into velocity mode and the
Fast Stop Ramp is used.
For more information, see Following Error Fault Details (p. 37).
20 Copley Controls Corp.
Xenus XTL User Guide Operational Theory
Diagram: Effects of Limits on Velocity Command
The following diagram illustrates the effects of the velocity loop limits.
Limited Velocity
Commanded Velocity
Vel Limit
Accel Limit Decel Limit
Velocity Loop Gains
The velocity loop uses these gains:
Gain Description
Vp - Velocity loop proportional The velocity error (the difference between the actual and the limited commanded
velocity) is multiplied by this gain. The primary effect of this gain is to increase
bandwidth (or decrease the step-response time) as the gain is increased.
Vi - Velocity loop integral The integral of the velocity error is multiplied by this value. Integral gain reduces the
velocity error to zero over time. It controls the DC accuracy of the loop, or the
flatness of the top of a square wave signal. The error integral is the accumulated
sum of the velocity error value over time.
Velocity Loop Gains Scalar
The Enable Gains Scalar feature increases or decreases the resolution of the units used to
express Vp and Vi, providing more precise tuning.
Velocity Loop Command and Output Filters
The velocity loop contains two programmable digital filters. The input filter should be used to
reduce the effects of a noisy velocity command signal. The output filter can be used to reduce the
excitation of any resonance in the motion system.
Two filter classes can be programmed: the Low-Pass and the Custom Bi-Quadratic. The LowPass filter class includes the Single-Pole and the Two-Pole Butterworth filter types. The Custom
Bi-Quadratic filter allows advanced users to define their own filters incorporating two poles and two
zeros.
For more information on the velocity loop filters, see the CME 2 User Guide.
Velocity Loop Outputs
The output of the velocity loop is a current command used as the input to the current loop.
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2.5.4: Position Mode and Position Loop
Position Loop Diagram
The amplifier receives position commands from the digital or analog command inputs, over the
CAN interface or serial bus, or from the CVM Control Program. When using digital or analog
inputs, the amplifier's internal trajectory generator calculates a trapezoidal motion profile based on
trajectory limit parameters. When using the CAN bus, serial bus, or CVM Control Program, a
trapezoidal or S-curve profile can be programmed. The trajectory generator updates the
calculated profile in real time as position commands are received.
The output of the generator is an instantaneous position command (limited position). In addition,
values for the instantaneous profile velocity and acceleration are generated. These signals, along
with the actual position feedback, are processed by the position loop to generate a velocity
command.
To bypass the trajectory generator while in digital or analog position modes, set the maximum
acceleration to zero. The only limits in effect will now be the velocity loop velocity limit and the
current limits. (Note that leaving the maximum acceleration set to zero will prevent other position
modes from operating correctly.)
The following diagram summarizes the position loop.
Position Loop
from motor encoder or resolver
from optional position encoder (on load)
+
+
+
Gain
Multiplier
Veloc ity
Command
Target
Po s it io n
Limits:
Max v elocity
Ma x accel
Ma x decel
Abort decel
Trajector y
Generator
Prof ile Velocity
Prof ile Acceleration
Limited Position
+
Feedback
Velocity Feed Forw ard (V ff)
Acceleration Feed Forw ard (Aff)
Position Proportional Gain (Pp)
-
Trajectory Limits
In position mode, the trajectory generator applies the following user-set limits to generate the
motion profile.
Limiter Description
Maximum Velocity Limits the maximum speed of the profile.
Maximum Acceleration Limits the maximum acceleration rate of the profile.
Maximum Deceleration Limits the maximum deceleration rate of the profile.
Abort Deceleration Specifies the deceleration rate used by the trajectory generator when motion is aborted.
Position Loop Inputs From the Trajectory Generator
The position loop receives the following inputs from the trajectory generator.
Input Description
Profile Velocity The instantaneous velocity value of the profile. Used to calculate the velocity feed forward
value.
Profile Acceleration The instantaneous acceleration/deceleration value of the profile. Used to calculate the
acceleration feed forward value.
Limited Position The instantaneous commanded position of the profile. Used with the actual position feedback to
generate a position error.
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Position Loop Gains
The following gains are used by the position loop to calculate the velocity command:
Gain Description
Pp - Position loop proportional The loop calculates the position error as the difference between the actual and
limited position values. This error in turn is multiplied by the proportional gain value.
The primary effect of this gain is to reduce the following error.
Vff - Velocity feed forward The value of the profile velocity is multiplied by this value. The primary effect of this
gain is to decrease following error during constant velocity.
Aff - Acceleration feed forward The value of the profile acceleration is multiplied by this value. The primary effect of
this gain is to decrease following error during acceleration and deceleration.
Gain Multiplier The output of the position loop is multiplied by this value before being passed to the
velocity loop.
Position Loop Feedback
Xenus supports two position feedback configurations
• Single sensor. Position loop feedback comes from the encoder or resolver on the motor.
• Dual sensor. Position loop feedback comes from the encoder attached to the load.
(Note that in either case, velocity loop feedback comes from the motor encoder or resolver.) For
more information, see Feedback (p. 16).
Position Loop Output
The output of the position loop is a velocity command used as the input to the velocity loop.
2.5.5: Input Command Types
The amplifier can be controlled by a variety of external sources: analog voltage or digital inputs,
CAN network (CANopen or DeviceNet), or over an RS-232 serial connection using ASCII
commands. The amplifier can also function as a stand-alone motion controller running an internal
CVM program or using its internal function generator.
2.5.6: Analog Command Input
Overview
The amplifier can be driven by an analog voltage signal through the analog command input. The
amplifier converts the signal to a current, velocity, or position command as appropriate for current,
velocity, or position mode operation, respectively.
The analog input signal is conditioned by the scaling, dead band, and offset settings.
Scaling
The magnitude of the command generated by an input signal is proportional to the input signal
voltage. Scaling controls the input-to-command ratio, allowing the use of an optimal command
range for any given input voltage signal range.
For example, in current mode, with default scaling, +10 Vdc of input generates a command equal
to the amplifier’s peak current output; +5 Vdc equals half of that.
Scaling could also be useful if, for example, the signal source generates a signal range between 0
and +10 Vdc, but the command range only requires +7.5 Vdc of input. In this case, scaling allows
the amplifier to equate +7.5 Vdc with the amplifier’s peak current (in current mode) or maximum
velocity (in velocity mode), increasing the resolution of control.
Dead Band
To protect against unintended response to low-level line noise or interference, the amplifier can be
programmed with a “dead band” to condition the response to the input signal voltage. The
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amplifier treats anything within the dead band ranges as zero, and subtracts the dead band value
from all other values. For instance, with a dead band of 100 mV, the amplifier ignores signals
between –100 mV and +100 mV, and treats 101 mV as 1 mV, 200 mV as 100 mV, and so on.
200
100
0
Output
-100
-200
Dead Band
0 200-200 -100 100
Input
Offset
To remove the effects of voltage offsets between the controller and the amplifier in open loop
systems, CME 2 provides an Offset parameter and a Measure function. The Measure function
takes 10 readings of the analog input voltage over a period of approximately 200 ms, averages
the readings, and then displays the results. The Offset parameter allows the user to enter a
corrective offset to be applied to the input voltage.
The offset can also set up the amplifier for bi-directional operation from a uni-polar input voltage.
An example of this would be a 0 to +10 Vdc velocity command that had to control 1000 rpm CCW
to 1000 rpm CW. Scale would be set to 2000 rpm for a +10 Vdc input and Offset set to -5V. After
this, a 0 Vdc input command would be interpreted as -5 Vdc, which would produce 1000 rpm CCW
rotation. A +10 Vdc command would be interpreted as +5 Vdc and produce 1000 rpm CW rotation.
Monitoring the Analog Command Voltage
The analog input voltage can be monitored in the CME 2 control panel and oscilloscope. The
voltage displayed in both cases is after both offset and deadband have been applied.
Analog Command in Position Mode
The Xenus Analog Position command operates as a relative motion command. When the amplifier
is enabled the voltage on the analog input is read. Then any change in the command voltage will
move the axis a relative distance, equal to the change in voltage, from its position when enabled.
To use the analog position command as an absolute position command, the amplifier should be
homed every time it is enabled. The Homing sequence may be initiated by CAN, ASCII serial, or
CVM Indexer program commands.
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2.5.7: PWM Input
Two Formats
The amplifier can accept a pulse width modulated signal (PWM) signal to provide a current
command in current mode and a velocity command in velocity mode. The PWM input can be
programmed for two formats: 50% duty cycle (one-wire) and 100% duty cycle (two-wire).
50% Duty Cycle Format (One-Wire)
The input takes a PWM waveform of fixed frequency and variable duty cycle. As shown below, a
50% duty cycle produces zero output from the amplifier. Increasing the duty cycle toward 100%
commands a positive output, and decreasing the duty cycle toward zero commands a negative
output.
Decreasing Duty Cycle Increasing Duty Cycle
P
WM Input
50 % Duty Cycle
Max +
Amplifier Output
0
Max -
The command can be inverted so that increased duty cycle commands negative output and vice
versa.
100% Duty Cycle Format (Two-Wire)
One input takes a PWM waveform of fixed frequency and variable duty cycle, and the other input
takes a DC level that controls the polarity of the output. A 0% duty cycle creates a zero command,
and a 100% duty cycle creates a maximum command level. The command can be inverted so that
increasing the duty cycle decreases the output and vice versa.
100%
Duty Cycle
PWM Input
Direction Input
Max +
100%
Duty Cycle
Amplifier Output
0
Min -
Failsafe Protection from 0 or 100% Duty Cycle Commands
In both formats, the amplifier can be programmed to interpret 0 or 100% duty cycle as a zero
command. This provides a measure of safety in case of a controller failure or a cable break.
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2.5.8: Digital Input
Three Formats
In position mode, the amplifier can accept position commands via two digital inputs, using one of
these signal formats: pulse and direction, count up/count down, and quadrature.
In all three formats, the amplifier can be configured to invert the command.
Pulse Smoothing
In position mode, the amplifier’s trajectory generator ensures smooth motion even when the
command source cannot control acceleration and deceleration rates.
When using digital or analog command inputs, the trajectory generator can be disabled by setting
the Max Accel limit to zero. (Note that when using the CAN bus, serial bus, or CVM Control
Program, setting Max Accel to zero prevents motion.)
Pulse and Direction Format
In pulse and direction format, one input takes a series of pulses as motion step commands, and
another input takes a high or low signal as a direction command, as shown below.
Pulse Input
Direction Input
Velocity
Command
The amplifier can be set to increment position on the rising or falling edge of the signal. Stepping
resolution can be programmed for electronic gearing.
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Count Up/Count Down Format
In the count up/count down format, one input takes each pulse as a positive step command, and
another takes each pulse as a negative step command, as shown below.
Up Input
Down Input
Velocity
Command
The amplifier can be set to increment position on the rising or falling edge of the signal. Stepping
resolution can be programmed for electronic gearing.
Quadrature Format
In quadrature format, A/B quadrature commands from a master encoder (via two inputs) provide
velocity and direction commands, as shown below.
A Input
B Input
Vel oc ity
Command
The ratio can be programmed for electronic gearing.
2.5.9: CVM Program
The Copley Virtual Machine (CVM) is a software program that runs motion control programs on
supported Copley Controls amplifiers. When a CVM program is running, the amplifier can receive
input commands from the CVM program.
For more information, see the Copley Indexer Program User’s Guide.
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2.6: CANopen Operation
2.6.1: CAN Network and CANopen Profiles for Motion
In position mode, the amplifier can take instruction over a two-wire Controller Area Network
(CAN). CAN specifies the data link and physical connection layers of a fast, reliable network.
CANopen is a set of profiles (specifications) built on a subset of the CAN application layer
protocol. These profiles specify how various types of devices, including motion control devices,
can use the CAN network in a highly efficient manner. Xenus supports the relevant CANopen
profiles, allowing it to operate in the following modes of operation: profile torque, profile velocity,
profile position, interpolated position, and homing.
2.6.2: Supported CANopen Modes
In profile torque mode, the amplifier is programmed with a torque command. When the amplifier is
enabled, or the torque command is changed, the motor torque ramps to the new value at a
programmable rate. When the amplifier is halted, the torque ramps down at the same rate.
In profile velocity mode, the amplifier is programmed with a velocity, a direction, and acceleration
and deceleration rates. When the amplifier is enabled, the motor accelerates to the set velocity
and continues at that speed. When the amplifier is halted, the velocity decelerates to zero.
In profile position mode, the amplifier is programmed with a velocity, a relative distance or
absolute position, and acceleration and deceleration rates. On command, a complete motion
profile is executed, traveling the programmed distance or ending at the programmed position. The
amplifier supports both trapezoidal and s-curve profiles.
In PVT mode, the controller sends the amplifier a sequence of points, each of which is a segment
of a larger, more complex move, rather than a single index or profile. The amplifier then uses
cubic polynomial interpolation to “connect the dots” so that the motor reaches each point at the
specified velocity at the programmed time.
Homing mode is used to move the axis from an unknown position to a known reference or zero
point with respect to the mechanical system. The homing mode is configurable to work with a
variety of combinations of encoder index, home switch, and limit switches.
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2.6.3: Architecture
As shown below, in a CANopen motion control system, control loops are closed on the individual
amplifiers, not across the network. A master application coordinates multiple devices, using the
network to transmit commands and receive status information. Each device can transmit to the
master or any other device on the network. CANopen provides the protocol for mapping device
and master internal commands to messages that can be shared across the network.
Feedback
S
oftw are Application
Master Controller
Xenus
Amplifier
CANopen
CANopen
CANopen
I/O
Xenus
Amplifier
I/O
Other
CANopen
Device
C
ontrol
Status
CAN port
CANopen
CAN Network
CAN port
CAN port
CAN port
Local Control
Sensor
Feedback
Local Control
Sensor
Motor
Motor
2.6.4: CAN Addressing
A CANopen network can support up to 127 nodes. Each node must have a unique and valid
seven-bit address (Node ID) in the range of 1-127. (Address 0 is reserved and should only be
used when the amplifier is serving as a CME 2 serial port multi-drop gateway.)
There are several basic methods for setting the CAN address, as described below. These method
can be used in any combination, producing a CAN address equal to the sum of the settings.
Addressing Method Description
Use switch If the address number <= 15, CAN address can be set using the CAN ADDR switch only.
Use inputs Use the amplifier’s programmable digital inputs (user selects how many (1-7) and which
inputs are used).
Use programmed value Program address into flash only.
For more information on CAN addressing, see CAN Interface (p. 109).
For more information on CANopen operations, see the following Copley Controls documents:
• CANopen Programmer’s Manual
• CML Reference Manual
• Copley Motion Objects Programmer’s Guide
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2.7: Limit Switches
2.7.1: Use Digital Inputs to Connect Limit Switches
Limit switches help protect the motion system from unintended travel to the mechanical limits. Any
of the digital inputs 2-12 can be can be programmed as positive or negative limit switch inputs.
With the amplifier operating as a CAN node, an input can also be programmed as a home limit
switch for CANopen homing operations.
2.7.2: Diagram: Sample Placement of Limit Switches
The following diagram shows these limit switches in use on a sample motion stage.
Mechanical Limits of Motion Stage
Negative
Limit
Sw itch
Home
Sw itch
Positive
Limit
Sw itch
2.7.3: How the Amplifier Responds to Limit Switch Activation
The amplifier stops any motion in the direction of an active limit switch, as described below. The
response is identical in current and velocity modes, and slightly different in position mode.
Mode Amplifier Response to Active Positive (or Negative) Limit Switch
Current
Velocity
Position Amplifier stops responding to position commands until the amplifier is disabled and re-enabled, or the fault
Amplifier prohibits travel in positive (or negative) direction. Travel in the opposite direction is still allowed.
Amplifier status indicator flashes green at fast rate.
Warning is displayed on CME 2 Control Panel and CME 2 Control Panel limit indicator turns red.
is cleared over the CANopen interface.
Amplifier status indicator flashes green at fast rate.
Warning is displayed on CME 2 Control Panel and CME 2 Control Panel limit indicator turns red.
Default behavior: If, after re-enabling the amp, the limit switch is still active, the amplifier will only allow
movement in the opposite direction.
“Hold position” behavior: If the *Hold position when limit switch is active option is set, the amplifier
prevents any motion while a limit switch is active.
CAUTION: If the amplifier is switched back to current or velocity mode with this option selected, the limit
switches will no longer function.
For more information on *Hold position when limit switch is active, see Digital Inputs (p. 93).
2.7.4: Using Custom Output to Signal Limit Switch Activation
In addition to the response described above, any of the amplifier’s digital outputs can be
configured to go active when a positive or negative limit switch is activated. For more information,
see Custom Digital Output Settings: Custom Event (p. 96).
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