Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 122)

Publication AG-UM008C-EN-P - February 2005
3-54 Configuring MicroLogix 1100/1200/1500 Controllers
The controller configured for Modbus RTU Master can initiate
messages using the Modbus command function codes listed in the
following table.
Modbus Error Codes
Upon receiving a Modbus command that is not supported or
improperly formatted, the controller configured for Modbus RTU Slave
will respond with one of the exception codes listed in the first table
starting on the next page.
Upon receiving a Modbus reply with an exception code, the controller
configured for the Modbus RTU Master posts a MSG error code listed
in the second table on the following page.
Write Single Coil
(1) 5 -
Write Single Holding Register
(1) 6 -
Echo Command Data 8 0
Clear Diagnostic Counters 8 10
Write Multiple Coils
(1) 15 -
Write Multiple Holding Registers
(1) 16 -
(1) Broadcast is supported for this command.
Command Function Code
(decimal)
Subfunction Code
(decimal)
Command Function Code
(decimal)
Subfunction Code
(decimal)
Read Coil Status 1 -
Read Input Status 2 -
Read Holding Registers 3 -
Read Input Registers 4 -
Write Single Coil
(1) 5 -
Write Single Holding Register
(1) 6 -
Write Multiple Coils
(1) 15 -
Write Multiple Holding Registers
(1) 16 -
(1) Broadcast is supported for this command.