Operating instructions

GasPoint
Page 3
Installation — System Design Specifications
Page 6
System Design Specifications:
Supply Voltage: 12 to 32 volts
Power Consumption: Catalytic Combustible Sensors: 100 mA @ 24 VDC
IR Combustible Sensors: 75 mA @ 24 VDC
Toxic /Oxygen Sensors: 40 mA @ 24 VDC
Relays: 50 mA per relay (150 mA total)
Memory: Non-volatile memory, a battery back-up is not necessary to retain values in the event of
power
outages.
Loop Resistance: 650 ohms maximum
Cable 4-20 mA: 3 conductor, 14 to 24 AWG; Relays: 3 conductor, 14 to 24 AWG
Sensor Separation Kit: 4 conductor, 16 to 22 AWG
Relays: 5 amp at 24 VDC or 115 VAC SPDT; LOW, HIGH and FAULT
Low/High Relays: Field selectable for normally energized/de-energized; latching/non-latching
Fault Relay: Energized; Non-latching
Sensor Separation Kit: Transmission Distances. See Table
Cable Installation
Transmission Range: The distance the 4-20 mA signal can travel is dependent on several factors including
the cable gauge. Maximum cable resistance is 650 ohms less the controller resistance.
The Tables below assume a constant 24 volt power supply (at 20°C) , copper wire and a Controller resistance of
250 ohms. The signal range from the Controller to the GasPoint takes into account the return loop, the distance
shown is from the Controller to the Transmitter. (Note the BW CR-4000 Controller has a resistance of only 120
ohms)
For other operating parameters use the formula below to establish the transmission range.
Formula: Maximum Distance =
{((V
P
— V
T
)/ I
c
)-R
C
}/(2xR
L
)
Where: V
P
= power supply voltage (minimum)
V
T
= transmitter supply voltage (minimum) 12 volt
I
c
= current through conductor See table 1A and 1B for factors
R
C
= total controller resistance
R
L
= line resistance per 350 meters (1,160 ft)
Table 1A: Transmitter with Catalytic/IR Combustible Sensor
(Maximum cable Lengths between Controller and Transmitter )
Conductor Size
Relays Not Used One Relay Connected Two Relays Connected Three Relays Connected
Sq mm AWG feet meters feet meters feet meters feet meters
0.64 22 3,356 1,022 2,368 722 1,830 557 1,491 454
0.75 20 5,336 1,626 3,767 1,148 2,910 887 2,371 722
1.0 18 8.476 2,583 5,983 1,823 4,623 1,409 3,767 1,148
1.5 16 13,474 4,106 9,511 4,106 7,749 2,240 5,988 1,825
I
c
Current Factor
0.12 0.17 0.23 0.28
Table 1B: Transmitter with Toxic/Oxygen Sensor
(Maximum cable Lengths between Controller and Transmitter )
Conductor Size
Relays Not Used One Relay Connected Two Relays Connected Three Relays Connected
Sq mm AWG feet meters feet meters feet meters feet meters
0.64 22 6,712 2,045 3.661 1,115 2,517 767 1,917 584
0.75 20 10,953 3,253 5,821 1,774 4,002 1,219 3,049 929
1.0 18 16,953 5,167 9,247 2,818 6,357 1,937 4,843 1,476
1.5 16 26,948 8,213 14,699 8,213 10,105 3,080 7,699 2,346
I
c
Current Factor
0.06 0.110 0.160 0.210