If set to `true(1)' then threshold alarms will be sent.
Each 15m and 24h current register counter can be assigned a
threshold value. When crossed, a threshold crossing alarm
will be sent for the interval if enabled. Raised alarm will
be cleared at end of a following fault free interval i.e.
one with all interval counter values below their threshold
values and with no UAT. Only one TC alarm per interval can be
raised, regardless of how many thresholds have been crossed.