DCA
Page 10
Figure 6.
PC DCA with DI Option Terminal Locations
Setup of DCA’s in Explosion-proof Enclosures.
The DCA in an explosion-proof enclosure (EX) in-
corporates a modification of the STD housing where
the connection terminals are replaced with pins on the
unit bottom panel. These pins are inserted in a
terminal block permanently mounted inside the base
of the explosion-proof enclosure.
To effect the calibration connections, unscrew the top
of the enclosure and pull the DCA up and out of the
enclosure base, exposing the terminal block. Figure 7
shows the block and its labeling. Figure 8 shows the
labeling used for units equipped with the DI Option.
Use the appropriate terminal locations figure to
connect the calibration equipment to the terminal
block in the enclosure base. Then re-connect the
DCA by aligning the pins on the bottom of the unit
housing with the holes in the terminal block. Press
down until the unit is seated firmly in the enclosure
base.
CAUTION
The EX DCA housing fits into the terminal
block in its correct orientation only. Note
the position of the connection “key”.
Attempting to “force” the unit in when the
pins are not aligned with the correct holes
will bend the pins.
Basic Calibration Hookup.
Use the terminal loca-
tions figure that is appropriate for the type of DCA
being checked, and connect the equipment described
in the calibration equipment table as shown in the
calibration hookup diagram, figure 9.
Set all low alarm pots fully counterclockwise. DCA
pots are equipped with slip clutches to prevent
damage in the event of over-turning. A slight change
in torque may be felt when a wiper stop is reached. If
unable to sense the stop, set pot 15 turns counter-
clockwise.
7
LNO - LOWER RELAY NORMALLY OPEN
4
LNC - LOWER RELAY NORMALLY CLOSED
2
5
3
+IN — LOWER ALARM CURRENT OR V INPUT
10
-IN — CURRENT OR VOLTAGE - INPUT
13
1
15
COM - COMMON
UNC - UPPER RELAY NORMALLY CLOSED
COM - COMMON
+IN — UPPER ALARM CURENT OR VINPUT
UNO - UPPER RELAY NORMALLY OPEN
ONE TERMINAL
STRIP PER
CARD POSITION
