-14-
6-3. Wiring Procedure
Terminal
block
Marking
Polarity
Function
TB1
P
+
Power input (24 VDC)
N
-
G
+
Gas concentration output
(4
–20 mADC)
H
-
E
Earth terminal
TB2
ZA1
1
st
stage gas alarm contact output
(Dry NO contact)
Max. load: 125 VAC or 30 VDC 0. 5 A (resistive load)
ZA2
2
nd
stage gas alarm contact output
(Dry NO contact)
Max. load: 125 VAC or 30 VDC 0. 5 A (resistive load)
ZC
Common for ZA1 and ZA2
TA
+
Trouble alarm
(NC open collector)
Max. load: 30 VDC, 30mA resistive load
TC
-
Trouble alarm common
(NO: Normally open; NC: Normally closed)
Terminal layout
○
+
○
-
○
+
○
-
○
+
○
-
CAUTION
The analog output line and power line of the gas detector are not isolated from each other.
When using the detector with external devices, provide isolation to prevent noise from other
power lines from interfering with the analog output of the detector.
When wiring, place wires to avoid potential noise sources (e.g., large power transformers,
motors, and powers supply units).
Ensure cables between the gas detector and external devices are connected correctly.
TB2’s gas alarm contact output is intended to be used with resistive loads only. If used with
inductive loads, back electromotive force will be generated, which may fail the operation of the
device or relay contacts.
WARNING
Turn off the gas detector before wiring to prevent electric shocks.
Ensure correct polarity when connecting the trouble alarm open collector (TA: + / TC: -). Due
to the built-in protection diode, incorrect polarities will cancel an active trouble alarm output.
Ground the detector to prevent electric shocks.