105BCommunication processor
12.5 Modbus communication
S7-1200 Programmable controller
602
System Manual, 11/2011, A5E02486680-05
MB_COMM_LOAD data block variables
The following table shows the public static variables stored in the instance DB for the
MB_COMM_LOAD that can be used in your program.
Table 12- 65 Static variables in the instance DB
Variable
Data type
Description
ICHAR_GAP
Word
Delay for Inter-character gap between characters. This parameter is specified
in milliseconds and is used to increase the expected amount of time between
received characters. The corresponding number of bit times for this parameter
is added to the Modbus default of 35 bit times (3.5 character times).
RETRIES
Word
Number of retries that the master will attempt before returning the no response
error code 0x80C8.
Table 12- 66 MB_COMM_LOAD execution condition codes
1
STATUS (W#16#)
Description
0000
No error
8180
Invalid port ID value (wrong port/hardware identifier for communication module)
8181
Invalid baud rate value
8182
Invalid parity value
8183
Invalid flow control value
8184
Invalid response timeout value (response timeout less than the 5 ms minimum)
8185
MB_DB parameter is not an instance data block of a MB_MASTER or MB_SLAVE
instruction.
1
In addition to the MB_COMM_LOAD errors listed above, errors can be returned from the underlying PtP communication
instructions.
See also