Siemens SIMATIC S7 Equipment Manual page 26

Data Communication with the PLC
Enabling alarms
Data record 1
4-4
Wire break monitoring
These bits can be used to enable/disable wire break monitoring for each posi-
tion sensor.
Wire break monitoring is performed indirectly by evaluating the reaction of
the position sensor to a START pulse from the SM 338. If the position sensor
does not react within a specified period of time, this is considered a wire
break.
Byte 1 can be used to enable or disable the end-of-cycle or diagnosis alarm.
7
Byte 1 0 0 0 0
Data record 1 consists of 14 bytes.
Data record 1 contains the following:
Assignment of the counters and the counter setting (4 x 3 bytes) for each
S
sensor
Setting of the cycle time (1 byte)
S
Setting of the sensor-related, synchronous mode (1 byte)
S
0
0 0
End-of-cycle alarm
Diagnosis alarm
0: Alarm disabled
(i.e., is not forwarded)
1: Alarm enabled
SM 338 Equipment Manual
(4) J31069-D401-U1-A0-7618