Modbus Rtu Master Execution Error Codes - Siemens SIMATIC S7 System Manual

9.3.2.4

Modbus RTU master execution error codes

The high numbered error codes (starting with 101) are errors that are returned by the
Modbus slave device. These errors indicate that the slave does not support the requested
function or that the requested address (either data type or range of addresses) is not
supported by the Modbus slave device.
The low numbered error codes (1 through 12) are errors that are detected by the
MBUS_MSG instruction. These error codes generally indicate a problem with the input
parameters of the MBUS_MSG instruction, or a problem receiving the response from the
slave. Parity and CRC errors indicate that there was a response but that the data was not
received correctly. This is usually caused by an electrical problem such as a bad connection
or electrical noise.
MBUS_CTRL
error code
0
1
2
3
4
9
10
S7-200 SMART
System Manual, V2.3, 07/2017, A5E03822230-AF
Description
No error
Invalid parity type
Invalid baud rate
Invalid timeout
Invalid mode
Invalid port number
Signal board port 1 missing or not configured
Libraries
9.3 Modbus RTU library
487