Siemens SIMEAS R-PMU, Manual, Page: 72 / 296

7
7.2 Fault Recorders
72
Digital Fault Recorder, SIMEAS R-PMU, Manual
E50417-H1076-C360-A5, Release 10.2012
7.2.1.2.1.2 Gradient Trigger (±dM/dt)
The gradient of a signal is the level change per time. For the TAR the trigger condition for alter-
nating signals is met, when the difference of two half cycle rms values is higher than the param-
eterized threshold for a distance of two periods. For DDAUs, the arithmetic means are compared
for a distance of two periods. A distinction is made between rising gradients (+dM/dt, i. e. positive
difference) and falling gradients (-dM/dt, i. e. negative difference).
They can be parameterized for all analog signals from tables 7-11 and 7-12 (not for symmetrical
components).
7.2.1.2.2 Binary Trigger
Status changes of the binary DAU inputs can be defined as trigger conditions. Thus, a record
can be started if a sensor changes to or leaves from the alarm state or for each state change.
The correspondence between physical and logical state change depends on the sensor type
(see table 7-14 and chapter 12.11.1).
For the definition of high and low levels, refer to chapter 16.1.4.
Retrigger blocking for binary signals
The retrigger blocking can be activated separately for every binary input. It is used to suppress
repeated recordings in the event of fast successive binary signal changes while recording. The
corresponding binary trigger is disabled for the preset retrigger blocking time. If the same binary
input is retriggered within the retrigger blocking time, the retrigger blocking will be restarted for
this input. All other active channels can retrigger the TAR and thus extend the fault record.
Table 7-14 Sensor types
Sensor Logical
state change
Physical
state change
Make contact Change to alarm state Low
→
High
Change from alarm state High
→
Low
Break contact Change to alarm state High
→
Low
Change from alarm state Low
→
High
Note
The retrigger blocking time can be defined longer than the recording time. In case of a wrong
configuration, this may unintentionally avoid recordings.