DCA
Page 2
Figure 1.
High - and Low-alarm Relay Configurations
Table 1.
DCA Alarm Types
NOTES:
1. Older DCA’s may use X1 for H1, X2 for H2, X3 for L1, and X4 for L2.
2. The “UPPER” and “LOWER” labeling on the DCA front panel is for reference only.
Configurations where “LOWER” terminals and pots pertain to the unit’s high alarm, for
example, are quite possible.
3. Relays in fail-safe alarms are DE-energized in the event of power loss to the unit.
Model Number
Designator
This Unit is...
This Unit signals an
“Alarm” condition when...
Its LED will be...
Relay(s)
S
Single Alarm
-
-
Only one relay installed
D
Dual Alarm
-
-
Two relays are installed
H1
High Fail-Safe
Input increases, and exceeds
Trip Point. (See Note 2).
OFF in alarm
ON in Non-alarm
DE-energized in alarm
Energized in Non-alarm
H2
High NON-Fail-Safe
Input increases, and exceeds
Trip Point. (See Note 2).
ON in Alarm,
OFF in Non-alarm
Energized in Alarm,
DE-energized in Non-alarm
L1
Low Fail-Safe
Input decreases, and drops
below Trip Point
(See Note 2)
OFF in alarm
ON in Non-alarm
DE-energized in alarm
Energized in Non-alarm
L2
Low NON-Fail-Safe
Input decreases, and drops
below Trip Point
(See Note 2)
ON in Alarm,
OFF in Non-alarm
Energized in Alarm,
DE-energized in Non-alarm
FAIL-SAFE RELAY ENERGIZED, LED ON
FAIL-SAFE RELAY DE-ENERGIZED, LED OFF
TIME
TRIP POINT
RESET
LOW-ALARM DCA
100 %
0 %
DEAD BAND
ANALOG
INPUT
VALUE
TRIP POINT
RESET
TIME
HIGH-ALARM DCA
100 %
0 %
DEAD BAND
ANALOG
INPUT
VALUE
