10
12.2
95-8616
Figure 9—GT3000 Wired Directly to UD20 Display Unit (Explosion-Proof)
+
–
24 VDC
UD20 DISPLAY UNIT
B2478
J2-6
J2-5
J2-4
J2-3
J2-2
J2-1
J2
NOTE 1 CONNECT THE GREEN DETECTOR LEAD TO THE
CHASSIS GROUND LUG ON THE INSIDE BOTTOM
OF THE UD20 DISPLAY UNIT ENCLOSURE.
NOTE 2 250 OHM RESISTOR REQUIRED FOR HART
MENU ACCESS.
NOTE 3 EXTERNAL HART COMMUNICATION DEVICES CAN BE
CONNECTED ACROSS THE 250 OHM RESISTOR,
ACROSS J2-5 AND J2-6, OR ACROSS J2-2 AND J2-3.
NOTE 4 JUNCTION BOX MUST BE ELECTRICALLY
CONNECTED TO EARTH GROUND.
NOTE 5 GROUND THE SHIELD AT THE POWER SOURCE
END ONLY.
SEE NOTES 2 & 3
SEE NOTE 5
GT3000
GAS DETECTOR
+
+
–
–
SHIELD
SHIELD
SENSOR
LOOP
POWER
LOOP
BLACK
RED
GREEN
SEE NOTE 1
+
–
24 VDC
UD20 DISPLAY UNIT
D2408
J2-6
J2-5
J2-4
J2-3
J2-2
J2-1
J2
NOTE 1 GROUND THE SHIELD AT THE POWER SOURCE
END ONLY.
NOTE 2 250 OHM RESISTOR REQUIRED FOR HART
MENU ACCESS.
NOTE 3 EXTERNAL HART COMMUNICATION DEVICES CAN BE
CONNECTED ACROSS THE 250 OHM RESISTOR,
ACROSS J2-5 AND J2-6, OR ACROSS J2-2 AND J2-3.
NOTE 4 JUNCTION BOXES MUST BE ELECTRICALLY
CONNECTED TO EARTH GROUND.
BLACK
RED
SEE NOTE 1
SEE NOTES 2 & 3
SEE NOTE 1
GT3000
GAS DETECTOR
SENSOR TERMINATION BOX
RED
RED
BLA
CK
BLACK
GREEN
+
+
–
–
SHIELD
SHIELD
SENSOR
LOOP
POWER
LOOP
Figure 10—GT3000 with Sensor Termination Box Wired to UD20 Display Unit (Explosion-Proof)
