DCA
Page 15
5.
Set input to desired low alarm trip point level.
6.
Turn appropriate low alarm adjustment pot (may
be labeled “UPPER” or “LOWER”) slowly clock-
wise. Observe LED and ohmmeter, and stop
turning at exact point where relay changes state.
Vary pot setting slightly above and below trip
point to “zero in” on exact setting.
If low alarm is configured as fail-safe, L1 in model
number, verify that appropriate LED for low alarm
is not lit. LED for non-fail-safe low alarm, L2 in
model number, will be lit.
7.
Verify desired setting by varying input above and
below trip point level (from step 6) and observing
both LED and ohmmeter to confirm change of
relay state at, and below trip point setting.
NOTE
Units equipped with any Manual Reset
Option have external push buttons that
must be pressed to reset the relays once
they have been tripped.
Setting High-Alarm Trip Points.
Remember that the
“UPPER” and “LOWER” labeling on the DCA is for
reference purposes only. The DCA can be ordered
without high alarms, as in a “low/low” configuration.
Dual alarm units, on the other hand, can be ordered
with either one or both relays configured as high
alarms
.
Refer to the unit’s model number to determine the
alarm configuration, and perform the following proce-
dure for each installed high alarm.
1.
Check model number to verify correct power
input, and apply 117 or 240 Vac; 24 or 45 Vdc, as
appropriate.
2.
Make sure that ohmmeter in calibration setup is
connected to appropriate -NO or -NC terminals, as
desired.
3.
Apply 0% of application’s input span (current or
voltage, as appropriate) to DCA.
If high alarm is configured as fail-safe, H1 in
model number, verify that appropriate LED for that
alarm is lit. LED for non-fail-safe low alarm, H2 in
model number, will not be lit.
4.
Note ohmmeter reading.
In a high alarm, 0% input is a non-alarm condi-
tion. If connected to
X
NO and COM terminals
(
X
= U or L, UPP or LOW; NO = normally open),
Resistance across the terminals in a fail-safe
alarm is
zero
. In a non-fail-safe alarm resis-
tance will be near
infinite
.
If connected to
X
NC and COM terminals, resis-
tance is
infinite
in fail-safe,
zero
in non-fail-safe
alarms.
5.
Set input to desired high alarm trip point level.
6.
Turn appropriate high alarm adjustment pot (may
be labeled “UPPER” or “LOWER”) slowly clock-
wise. Observe LED and ohmmeter, and stop
turning at exact point where relay changes state.
Vary pot setting slightly above and below trip
point to “zero in” on exact setting.
If high alarm is configured as fail-safe, H1 in
model number, verify that appropriate LED for that
alarm is not lit. LED for non-fail-safe high alarm,
H2 in model number, will be lit.
7.
Verify desired setting by varying input above and
below trip point level (from step 6) and observing
both LED and ohmmeter to confirm change of
relay state at, or above trip point setting.
NOTE
Units equipped with any Manual Reset
Option have external push buttons that
must be pressed to reset the relays once
they have been tripped.
