Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 121)

Publication AG-UM008C-EN-P - February 2005
Configuring MicroLogix 1100/1200/1500 Controllers 3-53
Modbus Commands
The controller configured for Modbus RTU Slave responds to the
Modbus command function codes listed in the table starting below.
30517 Element Number of Error Request 4
30518 Function Code 1 Message Counter - Read Single Output Coil 4
30519 Function Code 2 Message Counter - Read Discrete Input Image 4
30520 Function Code 3 Message Counter - Read Single Holding Register 4
30521 Function Code 4 Message Counter - Read Single Input Register 4
30522 Function Code 5 Message Counter - Set/Clear Single Output Coil 4
30523 Function Code 6 Message Counter - Read/Write Single Holding Register 4
30524 Function Code 8 Message Counter - Run Diagnostics 4
30525 Function Code 15 Message Counter - Set/Clear for Block of Output Coils 4
30526 Function Code 16 Message Counter - Read/Write for Block of Holding Registers 4
30527 Modem Status 4
30528 Total messages responded to by this slave 4
30529 Total messages to this Slave 4
30530 Total Messages Seen 4
30531 Link Layer Error Count 4
30532 Link Layer Error 4
31501 to 31566 Read Only System Status File 4
40001 to 40256 Read/Write Modbus Holding Register space (1st Holding Register file). 3, 6, 16
40257 to 40512 Read/Write Modbus Holding Register space (2nd Holding Register file). 3, 6, 16
40513 to 40768 Read/Write Modbus Holding Register space (3rd Holding Register file). 3, 6, 16
40769 to 41024 Read/Write Modbus Holding Register space (4th Holding Register file). 3, 6, 16
41025 to 41280 Read/Write Modbus Holding Register space (5th Holding Register file). 3, 6, 16
41501 to 41566 Read/Write System Status File 3, 6, 16
41793 to 42048 Read/Write Modbus Holding Register space (6th Holding Register file). 3, 6, 16
Modbus
Addressing Modbus Address Reference Modbus Function 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 -