Siemens SIMATIC S5 Manual page 210

QVZ (time-out) QVZ (time-out) occurs when an addressable memory area on the IM 308-C
fails to return the READY signal (acknowledgment) within a certain time
after being addressed by the CPU.
Table 11-5 Reaction to interruption of bus communication or failure of a DP slave (with QVZ)
Failed DP Reaction
1 1
slave(s) slave(s) : : of CPU: of CPU:
Response
monitoring
2
No RUN
2
Yes RUN
No STOP
Yes STOP
1
QVZ (time-out) is triggered by default for the CPU. The reaction of the CPU to QVZ depends, for example, on
whether OBs 23 and 24 have been programmed and on the setting selected in the DX0 for the S5-135U CPUs.
2
The "QVZ" LED lights up.
ET 200 Distributed I/O System
EWA 4NEB 780 6000-02a
Failed
DP slave
Reaction of failed DP slave(s):
The inputs in the CPU are set to "0".
The outputs of the DP slaves are ...
frozen.
set to "0" when response time expires.
frozen.
set to "0" when response time expires.
IM 308-C – starting ET 200
Remaining DP slaves
Reaction of remaining DP slaves:
The inputs in the CPU are updated as
before. The outputs on the DP slaves
are ...
updated as before
updated as before.
set to "0".
Exception: If the CPU belongs to the
S5-115 7UB.. series, the outputs in the
process image up to byte 79 are set to "0"
and frozen as of byte 80.
set to "0".
11
11-11