A1n.o
or
A1n.c
(alarm x normally open or normally closed)
Displays and sets the setpoint alarm relay action to normally open (de-energised) or normally
closed (energised), when no alarm condition is present. A normally closed alarm is often used to provide a
power failure alarm indication.
A2Lo, A3Lo
&
A4Lo
(alarm low setpoint)
Displays and sets alarm 2, 3 & 4 low setpoints, see
A1Lo
for further description. Note: alarm relays
3 & 4 are only fitted as options.
A2Hi, A3Hi
&
A4Hi
(alarm high setpoint)
Displays and sets alarm 2, 3 & 4 high setpoints, see
A1Hi
for further description. Note: alarm
relays 3 & 4 are only fitted as options.
A2HY, A3HY
&
A4 HY
(alarm hysteresis [deadband])
Displays and sets the alarm hysteresis limit for alarm 2, 3 & 4, see
A1HY
for further description.
Note: alarm relays 3 & 4 are only fitted as options.
A2tt, A3tt
&
A4tt
(alarm trip time)
Displays and sets the alarm trip time for alarm 2, 3 & 4, see
A1tt
for further description. Note:
alarm relays 3 & 4 are only fitted as options.
A2rt, A3rt
&
A4 rt
(alarm reset time)
Displays and sets the alarm relay reset time for alarm 2, see
A1rt
for further description. Note:
alarm relays 3 & 4 are only fitted as options.
A2n.o
/
A2n.c, A3n.o
/
A3n.c
,
A4n.o
/
A4n.c
(alarm normally open or normally closed)
Displays and sets the setpoint alarm relay action for alarm 2, 3 & 4, see
A1n.o
/
A1n.c
for further
description. Note: alarm relays 3 & 4 are only fitted as options.
A
x
.SP
,
A
x
.t1
,
A
x
.t2
etc.
(relay operation independent setpoint or trailing)
- this function will not be
seen if both the high and low setpoints are set to
OFF
.
Each alarm may be programmed to operate with an independent setpoint setting or may be linked
(or trailing) to operate at a fixed difference to another relay setpoint. The operation is as follows: Alarm 1 (
AI
)
is always independent. Alarm 2 (
A2
) may be independent or may be linked to Alarm 1. Alarm 3 (
A3
) may be
independent or may be linked to Alarm 1 or Alarm 2. Alarm 4 (
A4
) may be independent or may be linked to
Alarm 1, Alarm 2 or Alarm 3. The operation of each alarm is selectable within the Function Setup Mode by
selecting, for example, (Alarm 4)
A4.SP
= Alarm 4 normal setpoint or
A4.t1
= Alarm 4 trailing Alarm 1 or
A4.t2
= Alarm 4 trailing Alarm 2 or
A4.t3
= Alarm 4 trailing Alarm 3. For trailing set points the setpoint value
is entered as the difference from the setpoint being trailed.
If the trailing setpoint is to operate ahead of the prime setpoint then the value is entered as a positive
number and if operating behind the prime setpoint then the value is entered as a negative number. For
example, with Alarm 2 set to trail alarm 1, if
A1Hi
is set to 1000 and
A2Hi
is set to 50 then Alarm 1 will trip at
1000 and alarm 2 will trip at 1050 (i.e. 1000 + 50). If Alarm 2 had been set at -50 then alarm 2 would trip at 950
(i.e. 1000 - 50). See the trailing alarm table which follows.
Page 13 of 46
LD4LNMAN-1.0-1
Alarm relay
contacts are
open if no alarm
condition present
Alarm relay
contacts are
closed if no alarm
condition present
Alarm relay
contacts close
during alarm
condition
Alarm relay
contacts open
during alarm
condition
Alarm normally open
Alarm normally closed
