GE CB Watch 3, Operating Manual

Page: 78 / 118

MA-037 - CB Watch 3 Operating Manual v7.0 - May 2020 Page 78 of 118
Where a percentage “p” margin is added to avoid spurious alarms.
If this function is not being monitored and no sensor is present, then the values should be
set as such to avoid any erroneous alarm:
HMI: Settings / Analogue channels
Figure 126 – Coil current and charge default settings
Coil charge
By looking at the historical data, we can determine the minimum and maximum values of
the coil currents recorded and the time the coil is energised (which should be roughly equal
to the reaction time measured). We can use them, as shown in the table below, to calculate
the min and max coil charge for both opening and closing operation:
Opening Closing
Minimum Maximum Minimum Maximum
Coil current A B C D
Time E F G H
Coil charge (AxE)x((100-
p)/100)
(BxF)x((100+
p)/100)
(CxG)x((100-
p)/100)
(DxH)x((100+
p)/100)
Figure 127 – Coil charge alarm threshold calculation
Where a percentage “p” margin is subtracted from the lowest figure or added to the highest
figure observed to avoid spurious alarms. For example, P could be set to 5 (%).
Coil circuit continuity
No thresholds are used as the coils are either “open circuit” or not and the TCW sensor acts
as a relay.
If this function is not being monitored and no sensor is present, then ensure that the system
is set as such to avoid any erroneous alarm:
HMI: Settings / Operations Monitoring
Figure 128 – Coil continuity default setting