Siemens SIMEAS R-PMU, Manual, Page: 182 / 296

13
13.2 Operator and Error Messages
182
Digital Fault Recorder, SIMEAS R-PMU, Manual
E50417-H1076-C360-A5, Release 10.2012
13.2.2 Behaviour with Critical Faults
The SIMEAS R-PMU not only records events but independently detects faults that prevent the
SIMEAS R-PMU from functioning properly.
The following monitoring features trigger a restart:
Monitoring
The SIMEAS R-PMU monitors all running processes in real time. The device records if a process
is not carried out properly. A watchdog timer signals a system restart if the watchdog is not
triggered regularly.
Status message
The CPU receives a status message from the individual data acquisition units (DAUs) every 60
seconds. This verifies the proper functioning of every DAU. A DAU failure triggers a device
restart. When a DAU status message fails, the measuring system is restarted. If this happens
three times within 10 minutes, the measuring system is switched off and the device remains in
group alarm state.
Watchdog timer
The CPU module is monitored by a process monitoring circuit (watchdog timer). The watchdog
timer checks whether the internal device messages arrive in time. With each correct arrival the
watchdog timer is restarted. If the timer is not restarted, the watchdog triggers a device restart
after 8 seconds have elapsed.
Note
If the device still malfunctions after restarting, the restart will be interrupted after two further
unsuccessful attempts. In this case, contact our hotline.