Copley Controls Corp. XTL User manual

Xenus XTL™User Guide
P/N 95-00875-000
Revision 3
June 2008

Xenus XTL User Guide
This page for notes.

Copley Controls Corp. 3
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

Table of Contents Xenus XTL User Guide
4Copley Controls Corp.
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: I2TTime Limit Algorithm ......................................................................................................................................................... 153
B.1: I2TAlgorithm ...................................................................................................................................................................... 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

Copley Controls Corp. 5
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.

About this Manual Xenus XTL User Guide
6Copley Controls Corp.
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.
!
DANGER
Exercise caution when installing and adjusting.
Failure to heed this warning can cause equipment damage, injury, or death.
Risk of electric shock.
!
DANGER
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.
!
DANGER
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 non-
latched 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.
!
DANGER
When operating the amplifier as a CAN node, the use of CME 2 or ASCII serial
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 non-
latched faults.
!
DANGER
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.
!
DANGER
Operate amplifiers within the specifications provided in this manual.
Failure to heed this warning can cause equipment damage, injury, or death.

Xenus XTL User Guide About this Manual
Copley Controls Corp. 7
Revision History
Revision Date DECO# Comments
1December 2007 16236 Initial release.
2February 2008 16714 Updated Multi-Mode Port Interface Diagram (p. 66).
3June 2008 17111 Updated Web page references and made other minor changes.

About this Manual Xenus XTL User Guide
8Copley Controls Corp.
This page for notes.

Copley Controls Corp. 9
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

Introduction Xenus XTL User Guide
10 Copley Controls Corp.
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 three-
phase 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
Resolver Sin/Cos Encoder Continuous
Current
Peak Current Vac
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
100 to
240
Aseparate +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.

Xenus XTL User Guide Introduction
Copley Controls Corp. 11
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
agateway 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.

Introduction Xenus XTL User Guide
12 Copley Controls Corp.

Copley Controls Corp. 13
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

Operational Theory Xenus XTL User Guide
14 Copley Controls Corp.
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.

Xenus XTL User Guide Operational Theory
Copley Controls Corp. 15
2.1.3: Power and Grounding Diagram
+24
VDC LOGIC
&
SIGNAL
POWER
RTN
PWM
INVERTER
L1
CONTROL
LOGIC
MAINS
L3
+5 Vdc
U
V
W
MOTOR
HALLS
ENCODER
CASE
ISOLATION BARRIER
+5 Vdc
DC BUSS(+)
DC BUSS(-)
L2
AMPLIFIER
CHASSIS
CONTROL
SYSTEM
ENABLE [IN1]
SIGNAL GND
SIGNAL GND
SHIELD
J8
J7
J1
J2
FRAME
(SAFETY)
GROUND
CONTROL
SIGNAL
GROUND
~
~-
+
~+
REGEN(-) REGEN(+)
SHIELD
BRAKE
+24 Vdc
+24 Vdc
GROUND
J3
J4
1760 PF
DC/DC
Cntrl
DC/DC
Converter
+5 Vdc @
400mA
PWM
STAGE
CONTROL
POWER
+5 Vdc
BRAKE
CAN
Bus
Ckt
CAN
Network
SIGNAL GND
J6

Operational Theory Xenus XTL User Guide
16 Copley Controls Corp.
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.

Xenus XTL User Guide Operational Theory
Copley Controls Corp. 17
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.
Target
Position
Position
Command
Actual CurrentDerived VelocityActual Position
Velocity
Command
Curr ent
Command
Limited
Velocity
Limited
Current
PWM
Command
Trajectory
Generator
Position
Loop
Velocity
Limiter
Cur rent
Limiter
Current
Loop
Motor/
Sensors
Limits
Velocity
Loop
FILTER
FILTER
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.

Operational Theory Xenus XTL User Guide
18 Copley Controls Corp.
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
PWM
Command
Current Limiter
Current Loop
Feedback (Actual Current)
Limits:
Peak Current
Continuous Current
Peak Current Limit Time
Current Integral Gain (Ci)
Current Proportional Gain (Cp)
Limited Current +
-
+
+Motor
Current Offset
Current Loop Inputs
•The amplifier’s analog or PWM inputs.
•Anetwork command, CANopen, DeviceNet, or RS-232 Serial.
•ACopley 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
Maximum current that can be constantly generated by the amplifier.
I2TTime Limit Maximum amount of time that the peak current can be applied to the motor before it must
be reduced to the continuous limit or generate a fault.
For more details, see I2TTime Limit Algorithm (p. 153).
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.
Ramp Rate of change in current command.

Xenus XTL User Guide Operational Theory
Copley Controls Corp. 19
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).

Operational Theory Xenus XTL User Guide
20 Copley Controls Corp.
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
Command Current
Command
Ve locity Lim ite r
Velocity Loop
Feedback (Derived Velocity)
Limits:
Velocity
Acceleration*
Deceleration*
Emergency Stop Deceleration*
*Not used w hen velocity loop is controlled by position loop. See "Velocity Loop Limits" f or details.
Velocity Integral Gain (Vi)
Velocity Proportional Gain (Vp)
Limited
Velocity +
-
+
+
Filter
Filte r
Inputs
In velocity mode, the velocity command comes from one of the following:
•The amplifier’s analog or PWM inputs.
•Anetwork command, CANopen, DeviceNet, or RS-232 Serial.
•ACopley 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).