System 57 Quick Start Guide    05701-M-5026 MAN0839 Issue 1 
 
8.5 5704 Gas Card and Catalytic Type Detector 
Catalytic detectors require a three wire connection and the detector documentation will 
indicate three connections S, 01 and NS, which are usually brown, white and blue 
respectively. At the System 57 end of the field cable, the three detector wires should each be 
connected to the respective matching S, 01 or NS terminal of the appropriate channel on the 
Quad Relay Interface Card that is attached to the required Four Channel Control Card. 
 
 
NS 
S 
01 
19 
17 
15 
Detector 
NS 
S 
01 
5704 Quad Card 
The diagram shows the detector connections for Channel 1. Channel 2, 3 and 4 connections 
are similar and their terminal connection numbers are shown in section 7. 
8.6 5704 Gas Card and 2 Wire Loop Powered Detectors 
Loop powered detectors require a two wire connection and the documentation will indicate 
the positive and negative loop connections, usually brown and blue respectively. 
At the System 57 end of the field cable the two detector wires should be connected to the S 
(positive) and 01 (negative) terminals of the appropriate channel on the Quad Relay 
Interface Card that is attached to the required Four Channel Control Card. 
8.6.1 4-20mA loop powered detector (measuring resistor in supply 
return) 
 
 
 
01 
- 
+ 
28 
27 
Detector 
S 
5704 Quad Card 
The diagram shows the detector connections for Channel 1. Channel 2, 3 and 4 connections 
are similar and their terminal connection numbers are shown in section 7. 
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