Teledyne 1220 - Multipoint flammable gas and vapor detection system - Manual (Page 21)

3-3
Multi-Channel Combustible Monitor Installation 3
Teledyne Analytical Instruments
Care must be observed to ensure that the sensor leads are not inadvert-
ently connected to the signal common (C) or to the power ground while
energized. (See Figure 3-1)
Note: The maximum loop resistance for cabling to each sensor
is 35 , i.e. the cabling and connections should not ex-
ceed 35 total, or 35 / 2 = 17.5 on each side of the
sensor (See Figure 3-2).
Note that the white wire resistance is not a limiting factor
in the Loop Resistance, i.e. its resistance is not included
in the Loop Resistance measurement. To measure the
Loop Resistance directly, short the RED and BLACK
Connections at the Sensor and measure the resistance
between RED and BLACK at the channel module end of
the cable.
Figure 3-1 Sensors Connections
W
W W W