Acyclic Communication Via Modbus Rtu; Write And Read Access Using Function Codes - Siemens SINAMICS G110M Function Manual

Communication via RS485
5.4 Communication using Modbus RTU
5.4.4

Acyclic communication via Modbus RTU

Acyclic communication or general parameter access is realized using the Modbus register
40601 ... 40722.
Acyclic communication is controlled using 40601. 40602 contains the function code (always
= 47 = 2F hex) and the number of the following user data. User data are contained in
registers 40603 ... 40722.
Overview of acyclic communication
40601
Error codes
1 hex: Invalid Length (invalid length)
2 hex: Invalid State (in the actual inverter state, this action is not permitted)
3 hex: Invalid function code (FC ≠ 2F hex)
4 hex: Response not ready (the response has still not been issued)
5 hex: Internal Error (general system error)
Incorrect access operations to parameters via data set 47 are logged in registers
40603 ... 40722. The error codes are described in the PROFIdrive profile.
5.4.5

Write and read access using function codes

Function codes used
For data exchange between the master and slave, predefined function codes are used for
communication via Modbus.
The Control Unit uses the following Modbus function codes:
FC 03: Holding register to read data from the inverter
FC 06: Write single register to write to individual register
FC 16: Write to multiple registers to write to several registers
130
Value in the register
40602
0 47 ...
1 47 Request
length
[bytes]
2 47 Response
length
[bytes]
2 47 0
40603 ... 40722
... Write values for acyclic access
Request data Activate acyclic access
Response data Response for a successful request
Error code Response for an erronous request
Function Manual, 01/2016, FW V4.7 SP6, A5E34229197B AC
Explanation
Fieldbuses