100/180 mm PAPERLESS GRAPHIC RECORDER: USER GUIDE
HA028910
Issue 13 Sep 16
User Guide
Page 78
4.3.3 CHANNEL/ALARM CONFIGURATION (Cont.)
ENABLE
Allows the alarm to be defi ned as Off, Unlatched, Latched or Trigger.
Off
Alarm is disabled and the remainder of the alarm confi guration is hidden.
Unlatched
Unlatched alarms become active when the trigger source becomes active and re-
main active until the source returns to a non-active state.
The indicator is on (fl ashing before acknowledgment - steady after acknowledge-
ment) until the alarm clears.
Alarm messages are printed if enabled in group confi guration.
Latched
Latched alarms become active when the trigger source becomes active and remain
active until the alarm is acknowledged AND the trigger source has returned to a non-
active state.
The indicator is on (fl ashing before acknowledgment - steady after acknowledge-
ment) until the alarm has been acknowledged AND the trigger source has returned
to a non-active state.
Alarm messages are printed if enabled in group confi guration.
Continuous jobs remain active only whilst the alarm trigger source is active. I.E. the
job fi nishes when the alarm clears, whether acknowledged or not.
Trigger
When triggered all associated jobs are initiated, and continuous jobs remain active
until the alarm clears. There is no alarm indication, and no messages are printed.
TYPE
This fi eld appears only when the alarm Enable is not selected Off. Each alarm can be defi ned as absolute
high, absolute low, deviation-in, deviation-out, rate-of-change rise or rate-of-change fall.
Absolute High
As shown in fi gure 4.3.3d, an absolute high alarm becomes active when the channel
value exceeds the threshold value. The alarm remains active until the channel value
falls below (Threshold minus hysteresis). If a dwell value is defi ned, the alarm does
not become effective until this dwell time has been exceeded.
Absolute Low
As shown in fi gure 4.3.3d, an absolute low alarm becomes active when the chan-
nel value falls below the threshold value. The alarm remains active until the channel
value exceeds (Thr hysteresis). If a dwell value is defi ned, the alarm does
not become effective until this dwell time has been exceeded.
Deviation in
As shown in fi gure 4.3.3e, a deviation-in alarm becomes active whenever the chan-
nel value enters the band: Reference ± Deviation. It remains active until the channel
value leaves the band: Reference ± (De Hysteresis). If a dwell value is de-
fi ned, the alarm does not become effective until this dwell time has been exceeded.
Deviation out
As shown in fi gure 4.3.3e, a deviation-out alarm is active whenever the channel value
leaves the band Reference ± Deviation. It remains active until the channel value
enters the band: Reference ± (Deviation - Hysteresis). If a dwell value is defi ned, the
alarm does not become effective until this dwell time has been exceeded.
Rate of change
As shown in fi gure 4.3.3f, rate of change alarms become active whenever the signal
value changes by more than a specifi ed amount within a specifi ed period. If a dwell
value is defi ned, the alarm does not become effective until this dwell time has been
exceeded. An averaging period can be set to remove the effects of sudden, but
short-lived changes, such as noise spikes on the signal.
Note: Alarm icons appear at the display, as described in section 3.
SETPOINT SOURCE
Allows the user to choose either a fi xed, user-defi ned value (constant) or the value of another point (input
channel, maths channel, totaliser etc.) to be chosen as the trigger point. In the latter it is possible, for
example, to trigger an alarm, when one channel’s value rises above, falls below etc. the value of a second
channel.
