ProSoft Technology MVI94-MCM-MHI - Manual (Page 83)

MVI94-MCM ♦ Flex I/O Platform Reference
Serial Communications Modbus Communication Module User Manual
ProSoft Technology, Inc. Page 83 of 109
March 29, 2011
5.4 Modbus Protocol Specification
The following pages give additional reference information regarding the Modbus
protocol commands supported by the MVI94-MCM.
5.4.1 Commands Supported by the Module
The format of each command in the list depends on the MODBUS Function Code
being executed.
The following table lists the functions supported by the module.
Function
Code Definition Supported in
Master Supported in
Slave
1 Read Coil Status X X
2 Read Input Status X X
3 Read Holding Registers X X
4 Read Input Registers X X
5 Set Single Coil X X
6 Single Register Write X X
8 Diagnostics X
15 Multiple Coil Write X X
16 Multiple Register Write X X
17 Report Slave ID X
22 Mask Write 4X X
23 Read/Write X
Each command list record has the same general format. The first part of the
record contains the information relating to the communication module and the
second part contains information required to interface to the MODBUS slave
device.