Siemens SIMATIC NET S7-300 Manual page 251

Substitute values if a problem occurs (only when operating as PROFINET IO
controller)
If there is a fault (device/submodule failed), you can find out which submodules
have failed by querying the status information IOCS / IOPS status. You then have
the option of setting substitute values.
7.8.6 FB 52 PNIO_RW_REC
FB52 is used both for the "read data record" and the "write data record" function in
PROFINET IO controller mode. FB52 can only execute one of the functions at any
one time. The "read data record" or "write data record" function is controlled by the
WRITE_REC parameter.
Example: The CP can be informed of the location ID and plant designation using
the "write data record" function. This is done using the maintenance data record
"IM1" with index AFF1
You will find details of the supported data records and their structure at the
following Internet address:
http://support.automation.siemens.com/WW/view/en/19289930
Call Interface
Call interface in FBD representation:
S7-CPs for Industrial Ethernet Configuring and Commissioning
Release 01/2007
C79000-G8976-C182-07
7 Programming FCs (Functions) and FBs for S7 Ethernet CPs
.
H
PNIO_RW_REC
WORD CPLADDR
WRITE_REC
BOOL
DONE
ID
WORD
ERROR
WORD
INDEX
STATUS
INT LEN
ANY RECORD
BOOL
BOOL
WORD
A -251