Error Information At The Output Retval - Siemens SIMATIC S7 F Manual

Fail-Safe Blocks
8.15.4

Error Information at the Output RETVAL

The blocks for F communication between CPUs (F_SENDBO, F_RCVBO,
F_SENDR and F_RCVR) call the SFBs 8 (USEND) and 9 (URCV) internally. In the
event of communication problems, these SFBs indicate the possible causes in their
STATUS. This STATUS is entered in the high byte of RETVAL if ERROR=1
(USEND or URCV).
The STATUS of the SFBs and thus the configuration of the high byte of RETVAL is
described in the System Software for S7-300/400, System and Standard Functions
reference manual.
The low byte of RETVAL has the following configuration:
Bit Cause
0 Reserved
1 Recipient outputs substitute values
2 ERROR bit of USEND set
3 ERROR bit of USEND set
4 ERROR bit of URCV set
5 Check value error (CRC) or internal error in
the sender or recipient CPU or in the CP
6 Watchdog error or
internal error in the sender or recipient
CPU or in the CP
7 TIMEOUT error or
internal error in the sender or recipient
CPU or in the CP
8-140
Remedies
Read out the cause in RETVAL on the receiving side
Communication problems: see high byte
Check the connection configuration, and download it
again
Check the connecting cable
Communication problems: see high byte
Check the connection configuration, and download it
again
Check the connecting cable
Communication problems: see high byte
Check the connection configuration, and download it
again
Check the connecting cable
Check whether CRC_IMP is identical on the send and
receive sides; if not, recompile the Safety Program ,
download it to the CPU, and execute a cold restart, or
Check the connection configuration, and download it
again
Check the connecting cable
or replace the CPU or CP
Check the connection configuration, and download it
again
Check the connecting cable
or replace the CPU or CP
Increase the TIMEOUT monitoring time, if necessary
Check the connection configuration, and download it
again
Check the connecting cable
or replace the CPU or CP
Fail-Safe Systems
A5E00085588-03