Trane Mobrus RTU TR1 Series User manual

TR1

Series VFD
Variable Frequency Drive
ModbusTM RTU
Instruction Manual
June, 2004 TR1-SVX02A-EN
175R5563

WARNING
!
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.
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.
WARNING
!
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.
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.
WARNING
!
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.

3
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

4
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.
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
Introduction
About This
Manual
What You
Should
Already Know
Assumptions
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.
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.
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.
suggested that you read this manual in its
entirety before you start programming since
important information can be found in all
sections.
References TR1TM Series VFD Installation and Operation
Manual, document number TR1-SVX10A-EN.
For specific information on installation and
operation of the variable frequency drive, refer
to the TR1 Series VFD Installation and
Operation Instruction Manual.

5
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.
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
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.
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.
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.
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.

6
The Modbus RTU interface to the TR1 Series
VFD requires drive parameter values selected
as shown. See the TR1 Series VFD Installation
and Operation Manual for details on selecting
and changing parameter values, if necessary.
Drive
Parameter
Settings for
Modbus RTU
Communica-
tion • Parameter 500, Protocol: Modbus RTU
• Parameter 501, Address: 001 - 247
• Parameter 502, Baud Rate: 300 - 9600
baud. (Factory default is 9600 baud.)
• Parameter 570, Modbus Parity/Frame:
select from the following, based on
application.
Even Parity/1 Stop
Odd Parity/1 Stop
No Parilty/1 Stop (factory default)
• Parameter 571, Modbus Communication
Timeout: 10 - 2000 ms. (Factory default
setting is 100 ms.)
Network
Connection
EIA-485 Connector
RTxD' (-)
RTxD (+)
COM
69
68
61
Pin 1
Connect the Modbus RTU control wiring to
drive terminals (+)68 and (-)69 on control card
as illustrated.
Use 18 - 24 AWG (1.5 mm) shielded, twisted
pair control wiring. Tighten to 4.5 in-lbs (0.5
Nm).
Shielded wiring must be used. Ground shield
to drive terminal 61, drive casing, or as
appropriate for the network application.
DIP switches 2 and 3, located on the main
control board of the drive directly above the
EIA-485 connector, can be used to terminate
drives on the Modbus network (see figure). In
addition to serial communication, switch 4 is
used to isolate a low voltage, external DC
power supply. The factory default switch
positions are ON (see table).
Drive DIP
Switch
Settings for
Network
Connection
Drive DIP Switches
SWITCH SETTING
Switch 1 No function
Switches 2 & 3 Used for terminating an EIA-485 interface. When
the drive is the first, last, or only device on a
network, switches 2 and 3 must be ON.
When the drive is in any other location on the
network, switches 2 and 3 must be OFF.
Switch 4 Separates the common potential of the internal 24
VDC supply from the common potential of external
24 VDC supply. When switch 4 is in the OFF
position, the external 24 VDC supply is isolated
from the drive. See the drive operation manual for
more information on switch 4.
Drive DIP Switche Settings

7
Modbus RTU
Message
Framing
Structure
The controllers are setup to communicate on
the Modbus network using RTU (Remote
Terminal Unit) mode, with each 8-bit byte in a
Coding System: 8-bit binary, hexadecimal 0-9, A-F
Two hexadecimal characters contained in each 8-bit
field of the message
Bits Per Byte: 1 start bit
8 data bits, least significant bit sent first
1 bit for even/odd parity; no bit for no parity
1 stop bit if parity is used; 2 bits if no parity
Error Check Field: Cyclical Redundancy Check (CRC)
A Modbus RTU message is placed by the
transmitting device into a frame with a known
beginning and ending point. This allows
receiving devices to begin at the start of the
message, read the address portion, determine
which device is addressed (or all devices, if
the message is broadcast), and to know when
the message is completed. Partial messages
are detected and errors set as a result.
The allowable characters transmitted for all
fields are hexadecimal 0-9, A-F. The adjustable
frequency drives monitor the network bus
continuously, including ‘silent’ intervals. When
the first field (the address field) is received, each
drive or device decodes it to determine
whether it is the addressed device.
Modbus RTU messages addressed to zero
are broadcast messages. No response is
needed on broadcast messages.
To ensure the attribute data returned is the
most current, each attribute access must
include one attribute only.
A typical message frame is shown below.
Start Address Function Data CRC Check End
T1-T2-T3-T4 8 Bits 8 Bits
n x 8 Bits 16 Bits T1-T2-T3-T4
Remote
Terminal
Unit
Start/Stop Field
Messages start with a silent interval of at least
3.5 character times. This is implemented as a
multiple of character times at the selected
network baud rate (shown as Start T1-T2-
T3-T4). The first field then transmitted is the
device address. Following the last transmitted
character, a similar interval of at least 3.5
character times marks the end of the
message. A new message can begin after
this interval.
The entire message frame must be transmitted
as a continuous stream. If a silent interval of
more than 1.5 character times occurs before
completion of the frame, the receiving device
flushes the incomplete message and assumes
that the next byte will be the address field of a
new message.
Similarly, if a new message begins earlier that
3.5 character times following a previous
message, the receiving device will consider it
a continuation of the previous message. This
will cause a timeout (no response from the
slave), since the value in the final CRC field is
not valid for the combined messages.
Typical Modbus RTU Message Structure
Modbus RTU
Message
Framing
Structure
(continued)
message contains two 4-bit hexadecimal
characters. The format for each byte is shown
below.

8
Address Field
The address field of a message frame contains
8 bits. Valid slave device addresses are in the
range of 0 – 247 decimal. The individual slave
devices are assigned addresses in the range
of 1 – 247. (0 is reserved for broadcast mode,
which all slaves recognize.) A master
addresses a slave by placing the slave address
in the address field of the message. When
the slave sends its response, it places its own
address in this address field to let the master
know which slave is responding.
Function Field
The function field of a message frame contains
8 bits. Valid codes are in the range of 1 – 255
decimal. When a message is sent from a
master to a slave device, the function code
field tells the slave what kind of action to
perform.
When the slave responds to the master, it
uses the function code field to indicate either
a normal (error-free) response, or that some
kind of error occurred (called an exception
response). For a normal response, the slave
simply echoes the original function code. For
an exception response, the slave returns a
code that is equivalent to the original function
code with its most-significant bit set to a logic
1. In addition, the slave places a unique code
into the data field of the response message.
This tells the master what kind of error
occurred, or the reason for the exception. See
the Exception Codes section in this manual
for definitions.
Data Field
The data field is constructed using sets of two
hexadecimal digits, in the range of 00 to FF
hexadecimal. These are made from one RTU
character. The data field of messages sent
from a master to slave device contains
additional information which the slave must
use to take the action defined by the function
code. This can include items like coil or register
addresses, the quantity of items to be handled,
and the count of actual data bytes in the field.
The data field can have a length of zero.
CRC Check Field
Messages include an error-checking field that
is based on a cyclical redundancy check (CRC)
method. The CRC field checks the contents
of the entire message. It is applied regardless
of any parity check method used for the
individual characters of the message. The CRC
value is calculated by the transmitting device,
which appends the CRC as the last field in
the message. The receiving device
recalculates a CRC during receipt of the
message and compares the calculated value
to the actual value received in the CRC field.
If the two values are not equal, a bus timeout
results.
The error checking field contains a 16-bit binary
value implemented as two 8-bit bytes. When
this is done, the low-order byte of the field is
appended first, followed by the high-order byte.
The CRC high-order byte is the last byte sent
in the message.
Coil/Register Addressing
All data addresses in Modbus messages are
referenced to zero. The first occurrence of a
data item is addressed as item number zero.
For example:
The coil known as ‘coil 1’ in a programmable
controller is addressed as coil 0000 in the data
address field of a Modbus message. Coil 127
decimal is addressed as coil 007EHEX (126
decimal).
Holding register 40001 is addressed as register
0000 in the data address field of the message.
The function code field already specifies a
‘holding register’ operation. Therefore, the
‘4XXXX’ reference is implicit. Holding register
40150 is addressed as register 0095BHEX (149
decimal).
Modbus RTU
Message
Framing
Structure
(continued)

9
Memory
Mapping:
Coils
This is primarily used to control drive operation
and to read out basic status information.
Coil 65 determines whether parameter
changes made via Modbus RTU are held in
the temporary memory (RAM) of the drive or
are, in addition, written to permanent memory
(EEPROM).
Coil
Number Description Signal Direction
1 – 16 Drive Control Word (see table) Master to Drive
17 - 32 Drive Speed or Setpoint Reference
0HEX = 0% Reference, the value set in
parameter 204.
4000HEX = 100% Reference, the value
set in parameter 205.
8000HEX = 200% Reference, the
maximum value that can be
transmitted via Modbus RTU.
In most cases, if references from multiple
sources are supplied to the drive, the drive
will respond to the sum of the references
Master to Drive
33 – 48 Drive Status Word (see table) Drive to Master
49 – 64 Open Loop Mode: Drive Output
Frequency
0HEX = 0% of the reference value set in
parameter 204.
4000HEX = 100% of the reference value
set in parameter 205.
Closed Loop Mode: Drive Feedback
Signal
0HEX = 0% of the reference value set in
parameter 204.
4000HEX = 100% of the Reference value
set in parameter 205.
Drive to Master
65 Parameter Write Control (Master to Drive)
0
Î
Parameter changes are written to
the drive’s RAM and are lost when
power is removed from the drive.
1
Î
Parameter changes are written to
the drive RAM and to its EEPROM
and are maintained when power is
removed from the drive.
Master to Drive
66 - 65536 Reserved

10
Coil 0 1
01 Preset Ref. LSB
02 Preset Ref. MSB
03 DC Brake No DC Brake
04 Coast stop No coast stop
05 Quick stop No quick stop
06 Freeze freq. No freeze freq.
07 Ramp stop Start
08 No reset Reset
09 No j og Jog
10 no function
11 Data not valid Data valid
12 Relay 1 OFF Relay 1 ON
13 Relay 2 OFF Relay 2 ON
14 Setup LSB
15 Setup MSB
16 No reversing Reversing
Memory
Mapping:
Coils
(continued)
Coil 0 1
33 Control not ready Control ready
34 Drive not ready Drive ready
35 Coasting Stop Safety closed
36 No alarm Alarm
37 Not in use
38 Not in use
39 Not in use
40 No warning Warning
41 Not at reference At reference
42 Hand mode Auto mode
43 Out of frequency range In frequency range
44 Stopped Running
45 No function No function
46 No voltage warning Voltage warning
47 Not in current limit Current limit
48 No thermal warning Thermal warning
Control Word Coil Description
Status Word Coil Description
Stop Commands
The precedence of the stop
commands is as follows:
1. Coast stop
2. Quick stop
3. DC Brake
4. Normal (Ramp) stop

11
Memory
Mapping:
Holding
Registers
Holding registers are used to read and write
drive parameters. They are standard Modbus
4x registers, 40001 through 4000F (see table
below). A number of read-out parameters are
provided in the 500 group of parameters to
allow detailed operational information read
through serial communications. A parameter
value is accessed by using the register number
that is 10 times its parameter number. For
example, parameter 201 is accessed through
register 2010. See the drive instruction manual
for valid parameter numbers and their
meanings.
For parameters with numeric data:
Refer to the Data Type table (on the following
page) for each parameter to determine if one
register (for 8 and 16-bit values) or two registers
(for 32-bit values) must be transferred.
Refer to the Conversion Index table (on the
following page) for each parameter, as shown
in the drive instruction manual, to properly
scale numeric values that are sent via
Modbus RTU.
For parameters that involve selecting from a
list, refer to the individual parameter description
in the drive instruction manual to determine
the numeric value associated with each
selection. This value is shown in brackets [ ] in
each parameter selection.
Parameters that involve alphanumeric data
can store up to 20 ASCII characters. Two
characters can be transferred in each register.
Holding Register Parameter Groups
Register
Number Description
00001– 00008 Reserved
00009 Used to specify the index number to be used when an indexed parameter is
accessed.
00010 – 00990 000 Parameter Group (parameters 001 through 099, as available)
01000 – 01990 100 Parameter Group (parameters 100 through 199, as available)
02000 – 02990 200 Parameter Group (parameters 200 through 299, as available)
03000 – 03990 300 Parameter Group (parameters 300 through 399, as available)
04000 – 04990 400 Parameter Group (parameters 400 through 499, as available)
05000 – 05990 500 Parameter Group (parameters 500 through 599, as available)
06000 – 06990 600 Parameter Group (parameters 600 through 699, as available)
07000 – 07990 700 Parameter Group (parameters 700 through 799, as available)
08000 – 08990 800 Parameter Group (parameters 800 through 899, as available)
09000 – 09990 900 Parameter Group (parameters 900 through 999, as available)

12
Memory
Mapping:
Numbering
When accessing a parameter value in the
drive, note the Conversion Index and Data
Type of the parameter. These are shown in
the parameter table in the back of the drive’s
instruction manual.
The conversion index is used to properly scale
the value that is transmitted over the serial
communications. This is necessary because
only integers are passed over the serial
communications. To represent decimal
numbers, a conversion factor is associated
with each conversion index. To convert a value
passed over the serial communications to the
actual value, simply multiply it by the index.
Example: Parameter 201, Minimum
Frequency, has a conversion index of -1.
The conversion factor is therefore 0.1. A
value of 150 that is transmitted via serial
communications, therefore, represents
150 x 0.1 = 15.0.
The data type indicates the number of bits
needed to transmit the number via serial
communications. 8 or 16 bit data occupy one
Modbus RTU register while 32 bit data requires
two registers.
Example: Parameter 515, Data Read-out:
Power kW, has a data type of 7. It is a
32-bit unsigned number. In order to read
the output power from the drive, it is
necessary to read two Modbus RTU
registers.
Index Factor
74 3.6
2 100.0
1 10.0
0 1.0
-1 0.1
-2 0.01
-3 0.001
-4 0.0001
Conversion
Index and
Data Type
Data Type Description
3 Integer 16
4 Integer 32
5 Unsigned 8
6 Unsigned 16
7 Unsigned 32
9 Text string
Conversion Index
Data Type
A coil or register number is offset by one from
the coil or register address. Coil and register
numbers start at 1 while the coil and register
addresses for them start at 0. Therefore, to
find a coil or register address from the number,
subtract 1.

13
Standard
Modbus
Functions
The drive’s Modbus RTU interface supports the following standard Modbus RTU functions.
01HEX Read Coil Status 03 HEX Read Holding Registers
(Example 3) (Example 10 & 11)
05 HEX Force Single Coil 06 HEX Preset Single Register
(Example 6) (Example 7, 8 & 11)
0F HEX Force Multiple Coils 10 HEX Preset Multiple Registers
(Examples 1, 2, 4 & 5) (Example 9 & 12)
The examples on the following pages demonstrate how to use these functions to control and
monitor drive operation. All communication examples assume that the drive’s Modbus RTU
address is 1.
Example 1 Start the Drive and Give It a Reference via ModbusRTU
Setting the Control Word and Serial Reference Coils
Modbus Function 0FHEX – Force Multiple Coils
Example Give the Drive a Reference via ModbusRTU
Setting the Control Word and Serial Reference Coils
Modbus Function 0FHEX – Force Multiple Coils
Example 3 Read Basic Drive Status Information
Reading the Status Word and Output Frequency/Feedback Coils
Modbus Function 01HEX – Read Coil Status
Example 4 Give the Drive a Ramp to Stop Command
Setting the Control Word Coils
Modbus Function 0FHEX – Force Multiple Coils
Example 5 Give the Drive a Coast to Stop Command
Setting the Control Word Coils
Modbus Function 0FHEX – Force Multiple Coils
Example 6 Set How the Drive Stores Parameter Values
Setting Coil 65
Modbus Function 05HEX – Force Single Coil
Example 7 Write a Parameter Value from a List of Choices
Writing a single register
Modbus Function 06HEX – Preset Single Register
Example 8 Write a 16 Bit Parameter
Writing a single register
Modbus Function 06HEX – Preset Single Register
Example 9 Write a 3 Bit Parameter
Writing two registers
Modbus Function 10HEX – Preset Multiple Registers
Example 10 Read a 3 Bit Parameter
Reading two registers
Modbus Function 03HEX – Read Holding Registers
Example 11 Read an Indexed Parameter and Read an 8 Bit Parameter
Setting the value of register 1 and reading a single register
Modbus Function 06HEX – Preset Single Register
Modbus Function 03HEX – Read Holding Registers
Example 1 Write a Text String
Writing multiple registers
Modbus Function 10HEX – Preset Multiple Registers
Example 13 Read a Text String
Reading multiple registers
Modbus Function 03HEX – Read Holding Registers
Communica-
tion
Examples

14
Start the Drive and Give It a 40% Reference via ModbusRTU
While this example shows both starting the drive and giving it a reference via Modbus RTU, it is
possible to simply give it a start command. To do this, force only coils 1 through 16.
ModbusRTU Function: 0FHEX (Force Multiple Coils)
Overview:
•Force coils 110 through 1610 to 047CHEX.
This is a run command. Refer to the description of the Control Word. Other Control
Words could also give a run command, depending on the other functions desired.
•Force coils 1710 through 3210 to 1999HEX.
Because a value of 4000HEX represents a 00% reference, the value for a 40%
reference is 999HEX.
Message from ModbusRTU Master to Drive
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6
Slave
Address
Function Coil Addr.,
High
Coil Addr.
Low
No. of Coils,
High
No. of Coils,
Low
Byte Count
01 0F 00 00 00 20 04
Byte 7 Byte 8 Byte 9 Byte 10 Byte 11 Byte 12
Force Coils
Addr. 0-7
Force Coils
Addr. 8-15
Force Coils
Addr. 16-23
Force Coils
Addr, 24-31
CRC Error Check
7C 04 99 19 37 43
ModbusRTU message string:
[0 ] [0F] [00] [00] [00] [20] [04] [7C] [04] [99] [ 9] [37] [43]
Run Command: 0000 0 00 0 00 = 047CHEX
(See the Control Word Coil Description)
[0 ] [0F] [00] [00] [00] [20] [04] [7C] [04] [99] [ 9] [37] [43]
Commanded Reference: 40% of 4000HEX = 999HEX
Message returned from Drive to ModbusRTU Master
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5
Slave Address Function Coil Addr.,
High
Coil Addr.
Low
No. of Coils,
High
No. of Coils,
Low
01 0F 00 00 00 20
Byte 6 Byte 7
CRC Error Check
54 13
Example 1
{
{

15
Give the Drive a 75% Reference via ModbusRTU
ModbusRTU Function: 0FHEX (Force Multiple Coils)
Overview:
•Force coils 1710 throu h 3210 to 3000HEX.
Because a value of 4000HEX represents a 100% reference, the value for a 75%
reference is 3000HEX.
The value of coil 11 must have previousl been set to 1 for the drive to respond to
the changed speed reference.
Message from ModbusRTU Master to Drive
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5
Slave Address Function Coil Addr.,
High
Coil Addr.
Low
No. of Coils,
High
No. of Coils,
Low
01 0F 00 10 00 10
Byte 6 Byte 7
CRC Error Check
55 C2
Example 2
{
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6
Slave Address Function Coil Addr.,
High
Coil Addr.
Low
# of Coils,
High
# of Coils,
Low
Byte Count
01 0F 00 10 00 10 02
Byte 7 Byte 8 Byte 09 Byte 10
Force Coils
Addr. 16-23
Force Coils
Addr, 24-31
CRC Error Check
00 30 E0 A4
ModbusRTU message string:
[01] [0F] [00] [10] [00] [10] [02] [00] [30] [E0] [A4]
Commanded Reference: 75% of 4000HEX = 3000HEX
Message returned from Drive to ModbusRTU Master

16
Read Basic Drive Status Information
(Read the status and the speed of the drive  or the value of its feedback
signal.)
While detailed status information can be read by accessing the Data Read-out parameters in
the 500 group of parameters and some other locations, it is also possible to read general drive
status by reading coils 33 through 64.
·Coils 33 through 48 contain the drive Status Word.
·Coils 49 through 64 contain the drive output speed during open loop operation and the
drive feedback value during closed loop operation.
ModbusRTU Function: 01HEX (Read Coil Status)
Overview:
•Read the value of coils 3310 through 6410.
Message from ModbusRTU Master to Drive
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5
Slave Address Function Coil Addr.,
High
Coil Addr.
Low
No. of Coils,
High
No. of Coils,
Low
01 01 00 20 00 20
Byte 6 Byte 7
CRC Error Check
3C 18
Modbus RTU message string:
[01] [01] [00] [20] [00] [20] [3C] [18]
Starting Coil Address = Coil Number – 1 = 33 – 1 = 3210 = 20HEX
[01] [01] [00] [20] [00] [20] [3C] [18]
Number of Coils to Read = 3210 = 20HEX
Message retur ed from Drive to ModbusRTU Master
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6
Slave
Address
Function # of
Bytes
Coil Data
33 - 40
Coil Data
41 - 48
Coil Data
49 - 56
Coil Data
57 - 64
01 01 04 07 0F FF 1F
Byte 7 Byte 8
CRC Error Check
CA 9E
Example 3
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{
CONTINUED ON NEXT PAGE

17
ModbusRTU message stri g:
[01] [01] [04] [07] [0F] [FF] [1F] [CA] [9E]
Status Word = 0F07 = 0000 1111 0000 0111
At Refere ce
Remote Mode
I Freque cy Ra ge
Ru i g
[01] [01] [04] [07] [0F] [FF] [1F] [CA] [9E]
Output Freque cy (for Ope Loop operatio )
4000HEX = 100%, so 1FFFHEX = 50%
If Parameter 204, MIN. REFERENCE = 10Hz
a d Parameter 205, MAX. REFERENCE = 60Hz,
the the output freque cy is 50% of the way betwee 10Hz a d
60Hz,
or 35Hz.
{ {
Co trol Ready
Drive Ready
Safety Closed
{
Example 3
(continued)

18
Give the Drive a Ramp to Stop Command
ModbusRTU Function: 0FHEX (Force Multiple Coils)
Overview:
Note: It isnt necessary to change the reference value to stop the drive. It also
isnt necessary to give a reference vie ModbusRTU in order to start the
drive.
•Force coils 110 throu h 1610 to 043CHEX.
This is a ramp stop command. Refer to the description of the Control Word. Other
Control Words could also give a ramp stop command, depending on the other
functions desired.
Message from ModbusRT Master to Drive
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6
Slave
Address
Function Coil Addr.,
High
Coil Addr.
Low
No. of Coils,
High
No. of Coils,
Low
Byte Count
01 0F 00 00 00 10 02
Byte 7 Byte 8 Byte 9 Byte 10
Force Coils
Addr. 0-7
Force Coils
Addr. 8-15
CRC Error Check
3C 04 F2 E3
ModbusRT message string:
[01] [0F] [00] [00] [00] [10] [02] [3C] [04] [F2] [E3]
Ramp Stop Command: 0000 0100 0011 1100 = 043CHEX
( ee the Control Word Coil Description)
Message returned from Drive to ModbusRT Master
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5
Slave Address Function Coil Addr.,
High
Coil Addr.
Low
No. of Coils,
High
No. of Coils,
Low
01 0F 00 00 00 10
Byte 6 Byte 7
CRC Error Check
54 07
Example 4
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19
Give the Drive a Coast to Stop Command
A ModbusRTU coasting stop command, when drive parameter 503 is set to allow coasting
stop commands via the serial bus, acts much like a sa ety interlock. The drive cannot run
in any mode until the coasting stop command is removed. The lower right corner o the
drives normal display will show N.READY when a coasting stop command is active.
ModbusRTU Function: 0FHEX (Force Multiple Coils)
Overview:
Note: It isnt necessary to change the re erence value to stop the drive. It also
isnt necessary to give a re erence via ModbusRTU in order to start the
drive.
•Force coils 110 throu h 1610 to 0474HEX.
This is a coast stop command. Refer to the description of the Control Word. Other
Control Words could also give a coast stop command, depending on the other
functions desired.
Message sent from the ModbusRT Master to the Drive
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6
Slave
Address
Function Coil Addr.,
High
Coil Addr.
Low
No. of Coils,
High
No. of Coils,
Low
Byte Count
01 0F 00 00 00 10 02
Byte 7 Byte 8 Byte 9 Byte 10
Force Coils
Addr. 0-7
Force Coils
Addr. 8-15
CRC Error Check
74 04 C4 E3
ModbusRT message string:
[01] [0F] [00] [00] [00] [10] [02] [74] [04] [C4] [E3]
Coast Stop Command: 0000 0100 0111 0100 = 0474HEX
(See the Control Word Coil Description)
Message returned from Drive to ModbusRT Master
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5
Slave Address Function Coil Addr.,
High
Coil Addr.
Low
No. of Coils,
High
No. of Coils,
Low
01 0F 00 00 00 10
Byte 6 Byte 7
CRC Error Check
54 07
Example 5
{

20
Set How the Drive Stores Parameter Values
(Set the drive to store parameter changes in EEPROM)
By default, parameter changes made via Modbus TU are only written to andom Access
Memory ( AM). When power to the drive is cycled, these changes are lost. Because it is
possible to write to parameters a large number of times using Modbus TU, writing values
by default to AM avoids subjecting the Electronically Erasable Programmable ead Only
Memory (EEP OM) to an excessive number of write operations. To write a parameter
change to the drives EEP OM, first write the value 1 to coil number 65. Then make the
parameter change. Afterwards, to keep future parameter changes from being permanent,
write the value 0 to coil number65.
ModbusRTU Function: 0 HEX (Force Single Coil)
Overview:
•Force coil number 6 10 to 1.
Message from ModbusRT Master to Drive
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5
Slave Address Function Coil Addr.,
High
Coil Addr.
Low
No. of Coils,
High
No. of Coils,
Low
01 05 00 40 FF 00
Byte 6 Byte 7
CRC Error Check
8D EE
ModbusRT message string:
[01] [05] [00] [40] [FF] [00] [8D] [EE]
Coil Address: Coil Number  1 = 65  1 = 6410 = 0040HEX.
Message returned from Drive to ModbusRT Master
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5
Slave Address Function Coil Addr.,
High
Coil Addr.
Low
No. of Coils,
High
No. of Coils,
Low
01 05 00 40 FF 00
Byte 6 Byte 7
CRC Error Check
8D EE
Example 6
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