ABB Relion 670 series Engineering Manual page 66

Section 6
Local HMI engineering
60
If the signal is still ON when a reset LED is done, the LED will illuminated again.
This occurs when the application configuration accesses the signal again in the next
cycle after reset. The thin dashed lines in
LED following the signal and reset, when no higher prior signal is given.
The LED illuminates always in steady mode.
LED operation mode LatchedReset-S
S1
S2
S3
S4
tMax
tRestart
Auto-
Reset
Man-
Reset
S1LED
S2LED
S3LED
S4LED
Illumination => = Steady
IEC08000400 V1 EN
Figure 44: LHMI: LED operation mode LatchedReset-S
This mode is useful to monitor signals that are involved in case of a disturbance,
see Figure 44. The signal state after the disturbance allows a fast overview about
the disturbance. To get always the situation of the last occurred disturbance, the
LEDs are reset after a predefined time (tReset). So this is the longest time a
disturbance can be monitored by the LED situation.
In case a second disturbance occurs before the tReset time has elapsed, see
45, the signals that are still ON at the end of tReset will return to ON with the next
application configuration cycle after tReset. To clear these LEDs, a second timer
tMax is used. TMax is started when the first signal of the disturbance changes to
ON. tMax is stopped, when tReset could clear all LEDs.
A disturbance runs for a maximum of some seconds, while tReset can be in the
range of 60 to 90 seconds.
The timer tReset and tMax are configured in PST as part of the function block
LEDGEN
Figure 43
= Flash
IEC08000400.vsd
1MRK511240-UEN B
shows the internal state of the
Engineering Manual
Figure
670 series