DCA
Page 12
APPROPRIATE
CALIBRATED
ADJUSTABLE
CURRENT
OR
VOLTAGE SOURCE
+
(SEE NOTE 1)
DCA
+IN
–IN
VDC or VAC
POWER SOURCE
+
–
+
–
NOTES:
Check unit model number for appropiate input source.
Check unit model number for appropriate power source.
X = U for upper or L for lower. Connect ohmmeter to "NO" for terminals of normally open relay, to
NC for normally closed. “#” is used in DPDT-equipped units to refer to the number of the alarm
output, as in UNO1 and LNC2.
1.
2.
3.
(SEE NOTE 2)
COM
XNO#
XNC#
OHMMETER
(SEE NOTE 3)
–
Figure 9.
The DCA Calibration Setup
Special Considerations for AR-equipped DCA’s.
Units equipped with the AR Option are factory-set for
specific alarm delay times ranging from 1 to 30
seconds (refer to Options listing). The AR is set and
fully calibrated according to customer requirements
before unit shipment.
The delay in an AR-equipped DCA’s transition from
normal to alarm condition makes the calibration of trip
points difficult, and a temporary disabling of the option
is therefore recommended during the calibration
procedures.
To defeat the AR Option, diodes on PC1 of the DCA
must be shorted. There is a diode for each installed
relay.
DCA’s in the STD housing must be partially disas-
sembled to access the AR diode(s). See figure10.
Figures 11 and 12 show the location of the diodes on
the various types of AR-equipped DCA.
Access to the AR diode(s) on PC-style DCA’s may be
difficult if the unit being calibrated is already installed
in its rack. Moore Industries offers an Extender Card
accessory for calibrating units under these circum-
stances.
The Extender, P/N 350-513-00, mates with the
connector on the PC-style DCA, and then plugs in to
the rack so that the unit is clear of the rack front,
allowing for access to the diode(s).
Calibration Procedures
Before beginning the actual calibration of the DCA,
check the unit’s model number to verify that the
correct power supply and input simulator is being
used. Make sure that the appropriate connections are
made as shown in the figures of the preceding
section.
Using the Calibration Procedures.
The Calibration
Procedures section is divided into subsections that
describe first low alarm, then high alarm trip point
setting. The procedure for calibrating the DCA dead
band, for units equipped with the AD Option, should
be conducted after the trip points are set.
If the DCA to be calibrated is equipped with the TT
Option, skip to and complete the procedure in the
section entitled “Calibrating DCA’s Equipped with the
TT Option”.
