TR1 VFD-SVX02A, Trane(1)

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June, 2004
TR1-SVX02A-EN
175R5563
Equipment Hazard!
Rotating shafts and electrical equipment
can be hazardous. Therefore, it is strongly
recommended that all electrical work
conform to National Electrical Code (NEC)
and all local regulations. Installation, start-
up and maintenance should be performed
only by qualified personnel. Failure to
follow the NEC or local regulations could
result in death or serious injury.
Unintended Start!
In Auto Mode, a start signal via digital
inputs may cause drive to start at any time.
The drive, motor, and any driven equipment
must be in operational readiness. Failure
to be in operational readiness in Auto Mode
could result in death, serious injury, or
equipment or property damage.
CAUTION
Electrostatic Discharge!
Electronic circuit card components are
sensitive to electrostatic discharge (ESD).
ESD can reduce performance or destroy
sensitive electronic components. Follow
proper ESD procedures during installation
or servicing to prevent damage.
Motor control equipment and electronic controls are
connected to hazardous line voltages. When servicing
drives and electronic controls, there will be exposed
components at or above line potential. Extreme care
should be taken to protect against shock. Stand on an
insulating pad and make it a habit to use only one hand
when checking components. Always work with another
person in case of an emergency. Disconnect power
whenever possible to check controls or to perform
maintenance. Be sure equipment is properly grounded.
Wear safety glasses whenever working on electric
control or rotating equipment.
Hazardous Voltage!
Touching electrical parts may be fatal, even after equipment has been
disconnected from the AC input line. To be sure that capacitors have fully
discharged, wait 14 minutes for 208 V and 480 V units and 30 minutes for 600 V
units over 25 hp after power has been removed before touching any internal
component. Failure to wait for capacitors to fully discharge before touching
internal components could result in death or serious injury.
Table of Contents
Overview
Introduction ............................................................................................ 4
About This Manual .................................................................................. 4
Assumptions ........................................................................................... 4
What You Should Already Know ........................................................... 4
References .............................................................................................. 4
Modbus RTU Overview .......................................................................... 5
TR1 Series VFD with Modbus RTU Option Overview ............................. 5
Network Connection
Network Connection ................................................................................ 6
Drive DIP Switch Settings for Network Connection ............................... 6
Drive Parameter Settings for Modbus RTU Communication ................. 6
Network Configuration
Remote Terminal Unit .............................................................................. 7
Modbus RTU Message Structure ............................................................ 7
Memory Mapping: Coils ......................................................................... 9
Memory Mapping: Holding Registers .................................................... 11
Memory Mapping: Numbering ............................................................... 12
Conversion Index and Data Type ............................................................. 12
Communication Examples
Standard Modbus Functions .................................................................. 13
Example 1 Start the Drive and Give It a Reference via Modbus RTU .. 14
Example 2 Give the Drive a Reference via Modbus RTU ..................... 15
Example 3 Read Basic Drive Status Information ................................. 16
Example 4 Give the Drive a Ramp to Stop Command ......................... 18
Example 5 Give the Drive a Coast to Stop Command ......................... 19
Example 6 Set How the Drive Stores Parameter Values ...................... 20
Example 7 Write a Parameter Value from a List of Choices ................ 21
Example 8 Write a 16 Bit Parameter ...................................................... 22
Example 9 Write a 32 Bit Parameter ...................................................... 23
Example 10 Read a 32 Bit Parameter .................................................... 24
Example 11 Read Indexed Parameter and Read 8 Bit Parameter ....... 25
Example 12 Write a Text String .............................................................. 27
Example 13 Read a Text String .............................................................. 28
Exception Codes ..................................................................................... 29
3
Introduction
This manual provides comprehensive
instructions on the set up and operation of
the Modbus RTU protocol for the TR1 Series
VFD variable frequency drive to communicate
over a Modbus network.
For specific information on installation and
operation of the variable frequency drive, refer
to the
TR1 Series VFD Installation and
Operation Instruction Manual
.
About This
Manual
This manual is intended to be used for both
instruction and reference. It only briefly
describes the basics of the Modbus protocol
whenever necessary to gain an understanding
of the Modbus RTU for the TR1 Series VFD.
suggested that you read this manual in its
entirety before you start programming since
important information can be found in all
sections.
This manual is also intended to serve as a
guideline when you specify and optimize your
communication system. Even if you are an
experienced Modbus programmer, it is
Assumptions
This manual assumes that you have a
controller that supports the interfaces in this
document and that all the requirements
stipulated in the controller, as well as the TR1
Series VFD, are strictly observed, along with
all limitations therein.
What You
Should
Already Know
The TR1 Series VFD Modbus RTU is designed
to communicate with any controller that
supports the interfaces defined in this
document. It is assumed that you have full
knowledge of the capabilities and limitations
of the controller.
References
TR1
TM
Series VFD Installation and Operation
Manual
, document number TR1-SVX10A-EN.
4
Modbus RTU
Overview
The common language used by all Modicon
controllers is the Modbus RTU (Remote
Terminal Unit) protocol. This protocol defines
a message structure that controllers will
recognize and use, regardless of the type of
networks over which they communicate. It
describes the process a controller uses to
request access to another device, how it
will respond to requests from the other
devices, and how errors will be detected
and reported. It establishes a common
format for the layout and contents of
message fields.
queries
). The other devices (slaves) respond
by supplying the requested data to the
master, or by taking the action requested in
the query.
The master can address individual slaves, or
can initiate a broadcast message to all slaves.
Slaves return a message (called a
response
)
to queries that are addressed to them
individually. Responses are not returned to
broadcast queries from the master.
The Modbus RTU protocol establishes the
format for the master’s query by placing into
it the device (or broadcast) address, a
function code defining the requested action,
any data to be sent, and an error-checking
field. The slave’s response message is also
constructed using Modbus protocol. It
contains fields confirming the action taken,
any data to be returned, and an error-
checking field. If an error occurs in receipt of
the message, or if the slave is unable to
perform the requested action, the slave will
construct an error message and send it in
response, or a timeout will occur.
During communications on a Modbus RTU
network, the protocol determines how each
controller will know its device address,
recognize a message addressed to it,
determine the kind of action to be taken,
and extract any data or other information
contained in the message. If a reply is
required, the controller will construct the reply
message and send it.
Controllers communicate using a master-
slave technique in which only one device
(the master) can initiate transactions (called
TR1 Series
VFD with
Modbus RTU
Option
Overview
The TR1 Series variable frequency drive
communicates in Modbus RTU format over
an EIA-485 (formerly RS-485) network.
Modbus RTU allows access to the drive
Control Word and Bus Reference.
It is also possible to access the drive
parameters, read their values, and, where
possible, write values to them. This permits
a range of control possibilities, including
controlling the drive setpoint when its internal
PID controller is used.
The Control Word allows Modbus to control
several important functions of the drive:
• Start
• Stop (in several ways):
Coast stop
Quick stop
DC Brake stop
Normal (ramp) stop
• Reset after a fault trip
• Run at a variety of preset speeds
• Run in reverse
• Change the active setup
• Control the drive's two built-in relays
The Bus Reference is commonly used for
speed control.
5
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