
370 Fieldbus control through the embedded fieldbus interface (EFB)
Modbus function codes
The table below shows the Modbus function codes supported by the embedded
fieldbus interface.
400005
Default: Actual value 1 (
).
The selection can be changed using parameter
.
400006
Actual value 2 (
).
The selection can be changed using parameter
.
400007…400014
Data in/out 7…14.
Selected by parameters
400015
…
400089
Unused
400090
…
400100
Error code access. See section
Error code registers (holding registers
(page
).
400101
…
465536
Parameter read/write.
Parameters are mapped to register addresses according to parameter
Code
Function name
Description
01h
Read Coils
Reads the 0/1 status of coils (0X references).
02h
Read Discrete Inputs
Reads the 0/1 status of discrete inputs (1X
references).
03h
Read Holding Registers
Reads the binary contents of holding registers (4X
references).
05h
Write Single Coil
Forces a single coil (0X reference) to 0 or 1.
06h
Write Single Register
Writes a single holding register (4X reference).
08h
Diagnostics
Provides a series of tests for checking the
communication, or for checking various internal error
conditions.
Supported subcodes:
• 00h Return Query Data: Echo/loopback test.
• 01h Restart Comm Option: Restarts and initializes
the EFB, clears communications event counters.
• 04h Force Listen Only Mode
• 0Ah Clear Counters and Diagnostic Register
• 0Bh Return Bus Message Count
• 0Ch Return Bus Comm. Error Count
• 0Dh Return Bus Exception Error Count
• 0Eh Return Slave Message Count
• 0Fh Return Slave No Response Count
• 10h Return Slave NAK (negative acknowledge)
Count
• 11h Return Slave Busy Count
• 12h Return Bus Character Overrun Count
• 14h Clear Overrun Counter and Flag
ACS180 FW.book Page 370 Tuesday, March 9, 2021 2:25 PM