AutomationDirect DURAPULSE GS3-2010, User Manual

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5–75
Types of Messages Sent to GS Drives
There are three different types of messages typically be sent to GS Drives:
1) Read Registers (Function Code 3).
2) Write Multiple Registers (Function Code 16).
3) Write Single Register (Function Code 6).
Format of “Read Registers” Messages:
Format of “Write Multiple Registers” Messages:
Format of “Write Single Register” Messages:
Example Message:
Write a value of 60Hz to P9.26 and a value of 1 to P9.27 =
01 10 09 1b 00 02 04 02 58 00 01 5a 66
We receive a good reply = 01 10 09 1b 00 02 a3 9f
Sending message (13 characters from above) = 7.4 ms (0.00744796)
Reply message (8 characters from above) = 4.6 ms (0.004583)
For more specific information on how Modbus messages are formed, refer to the
Modbus specifications found at www.modbus.org.
Request:
XX = Node Address (1 Char)
06 = Function Code (1 Char)
XXXX = Register to Write to (2 Chars)
XXXX = Data to Write (2 Chars)
XXXX = 16 Bit CRC (2 Chars) Reply:
XX = Node Address (1 Char)
06 = Function Code (1 Char)
XXXX = Register to Write to (2 Chars)
XXXX = Data to Write (2 Chars)
XXXX = 16 Bit CRC (2 Chars)
Request:
XX = Node Address (1 Char)
10 = Function Code (Hex format) (1 Char)
XXXX = Starting Address to write to (2 Chars)
XXXX = Number of Registers to write to
(2 Chars)
XX = Number of bytes of data to write
(1 Char)
XXXX… = Depends upon Request
(2 Chars per Register requested)
XXXX = 16 Bit CRC (2 Chars)
Reply:
XX = Node Address (1 Char)
10 = Function Code (Hex format)(1 Char)
XXXX = Starting Address to write to (2 Chars)
XXXX = Number of Registers to write to
(2 Chars)
XXXX = 16 Bit CRC (2 Chars)
Request:
XX = Node Address (1 Char)
03 = Function Code (1 Char)
XXXX = Starting Address to read (2 Chars)
XXXX = Number of Registers to read (2 Chars)
XXXX = 16 Bit CRC (2 Chars) Reply:
XX = Node Address (1 Char)
03 = Function Code (1 Char)
XX = Byte count of data being sent from Slave
(1 Char)
XXXX… = Depends upon Request
(2 Chars per Register requested)
XXXX = 16 Bit CRC (2 Chars)
Chapter 5:
DURA
PULSE MODBUS Communications
DURA
PULSE AC Drive User Manual 1st Ed. Rev. D 05/2013