GASMAX II + GDS-IR Operation & Maintenance Manual, Revision 1.1
Page 11
CONNECTING DC POWER & OUTPUT SIGNAL WIRING
To access the GASMAX signal and power connections, remove the cover on the GASMAX II explosion-
proof enclosure, loosen the 2 thumbscrews holding the display assembly and remove it. The display will
remain connected to the IO/Power Supply PCB mounted in the back of the enclosure by a short ribbon
cable. Route the power and signal wires through the conduit entry and connect to
terminal block “
TB2
”.
Plus 24VDC connects to TB2-1. DC Ground connects to TB2-4. Channel One 4-20mA output is available on
TB2-2 and Channel Two 4-20mA output is available on TB2-3.
GDS Corp always recommends using shielded wire for signal and power cable.
Figure 3-1: GASMAX II + GDS-IR Power & Signal Wiring
ibbon to isplay
IO/Power upply
Bridge ensor
E
C
O
M
C
PW
O
O
G
B
B
TB2
–
1: +12-30VDC Input
TB2
–
2: Channel 1 (4-20mA Out)
TB2
–
3: Channel 2 (4-20mA Out)
TB2
–
4: Power / Signal Common
NOTE: The maximum distance 4-20 mA signals can
travel is dependent upon cable gauge, DC power
supply voltage level and input impedance of the
receiving device. Assuming a nominal 24 VDC
power supply, the maximum total loop resistance
is approximately 750 ohms.
Examples:
#18GA, 0.0064 ohm/ft => 11 miles
#24GA, 0.026 ohms/ft => 2.7 miles