AUTHORIZED DISTRIBUTOR - GasDetectorsUSA.com - Houston, Texas USA
Quickstart Guide
GASMAX II + GDS-IR Gas Monitor
IMPORTANT
-
Before installing the GASMAX II + GDS-IR,
make sure there are no toxic or combustible gases present.
Declassify the area if necessary.
Factors such as air movement by fans, prevailing winds,
convection, gas density, emission sources and environmental
variables should be taken into account when determining sensor
location. As with all sensors, the GASMAX II + GDS-IR should be
protected from falling or directed water, shock, vibration and dirt.
The GDS-IR sensor may be mounted either horizontally or
vertically (preferred). If mounted horizontally, make sure the GDS-
IR is protected from dripping water.
Use conduit and installation practices approved for the area
classification. When installed correctly, the GASMAX II + GDS-IR
is certified for use in areas rated Class 1, Div 1, Groups B, C & D.
S2
Ribbon to Display
1
2
4
3
P
W
R
O
U
T
4
-2
0
“E
C
H
E
M
”
O
U
T
4
-2
0
“L
E
L”
G
N
D
R
E
F
C
O
M
A
C
T
CATBEAD
S1
C7
C8
C1
C2
I/O Power Supply
Assy 10-0233
TB1
TB2
The GASMAX II power supply board is attached to the inside of
the explosion-proof housing (see Figure 1).
Connect the +DC power wire to TB2 pin 1. Connect the –DC
power to TB2 pin 4. DC voltage range is 18 to 30 VDC.
The 4-20mA output signal is available at TB2 pin 3. If an optional
toxic sensor is also connected to the GASMAX II, the toxic sensor
4-20mA output is available on TB2 pin 2.
Fig 1. GASMAX II Power Supply Board
INSTALLATION
POWER & 4-20mA WIRING
Optional Relay / RS-485 DIGITAL WIRING
The optional GASMAX II Alarm Relay / MODBUS interface board
is attached to the back of the GASMAX II display assembly.
RS-485 MODBUS wiring should be attached to TB2 pins 1 & 2.
Attach the signal shield wire to TB2 pin 3.
NOTE
: RS-485 is
polarity-sensitive and the wires on pins 1 & 2 may need to be
swapped for proper operation. If wiring in a “daisy chain”, terminals
4 & 5 are available for outgoing RS-485 wiring.
If necessary, select Jumper 1 (J1) position “A” to enable the RS-
485 termination resistor. This is typically done on the device
furthest from the RS-485 master controller.
Wiring for the three alarm relays is available on TB1. The normally
open, common and normally closed contacts are rated at 5A /
125VAC. Inductive loads should be protected by a reverse biased
diode or other transient suppression device.
U1
TB3
K2
K3
K1
J1
1
2
4
3
5
A
B
A
S
B
1
2
4
3
5
6
7
9
8
NO
C
NC
NO
C
NC
NO
C
NC
TB2
TB1
A
B
+
-
J1-A - Installs RS-485
Termination Resistor
J1-B - Omits RS-485
RS-485 “A” & “B” terminals are
connected internally. “S” is no-
connect for shield continuation
Remote Alarm Reset
Assy 10-0234
Relay 1
Relay 2
Relay 3
Fig 2. GASMAX II Alarm / MODBUS Board
- 832-615-3588
