Checkerrors Subroutine - Siemens SIMATIC S7 System Manual

9.4.4.2

CheckErrors subroutine

The CheckErrors subroutine checks the Open User Communication error codes and
determines if the program requires a state change. You use the same CheckErrors
subroutine for both the Active partner (client) and Passive partner (server).
Network 1: The program malfunctioned if there is no error code. Disconnect and then
reconnect to correct this problem.
Network 2: If one of the partners drops the connection, the program displays error codes 8,
12, 13, and 14. The partners are currently disconnected.
In all these cases, reconnect to the partner. Set the state to "Connect".
Network 3: If the error is a parameter error (error codes 1 - 7), stop the program because
there is a configuration error with one of inputs to the function. Correct this in the program.
If the error code is 9 (connect in progress), 10 (disconnect in progress), or 11 (send in
progress), stop because the state machine is broken. The state machine is programmed to
stay in the associated waiting state until the operation is complete, and these errors should
never occur.
If the error code is between 16 and 21, these constitute connect parameter errors and should
not appear here. If these errors occur, there is a malfunction, so stop program execution.
If the SEND and DISCONNECT instructions return error 24, there is no operation currently
pending. This probably means that the operation is complete; however, error 24 should
never appear based upon the state machine. Consider this an error, and go to stop.
Network 4: The program returns errors 15 and 31 if there are problems with the connection.
Disconnect and then reconnect to correct this problem.
S7-200 SMART
System Manual, V2.3, 07/2017, A5E03822230-AF
9.4 Open user communication library
Libraries
535