Siemens SIMATIC S7 Manual page 47

Termination of the
Connection in
Case of Error
MODBUS / TCP communication via the integrated PN interface of the CPU
2XV9450-1MB02; Manual edition 2.1
In special error situations, the FB terminates the connection:
•
Monitoring time for connection establishment exceeded
•
Monitoring time for receive exceeded
•
PI <> 0
•
received TI different to sent TI
•
Length in the header does not match the length information in the
telegram
Diagnosis
7-5