Configure the channels. See section 4.4.2.
Calibrate each detector according to the instructions supplied with the devices. Calibrate the
channels on the Quad Channel Input Module, as described in section 3.8.
9. Write the detector locations on the label inside the enclosure or cabinet.
10. Connect and power up the output devices one at a time. Attach them to the Relay Output
Modules, as shown in the wiring diagram in Figure 19, Appendix B.
Configure the relays. See sections 4.5.2 and 4.5.3.
11. Ensure that the display is cycling through the channels by pressing the RUN button.
3.6 Cabling
The cabling of gas detectors, fire detectors and alarms and other output devices is an important matter.
Cabling to a detector must be in accordance with the recognised standards of the appropriate authority
in the country concerned, and it must meet the electrical requirements of the detector.
• For non-IS devices, Crowcon recommends the use of steel wire armoured (SWA) cable. Suitable
explosion-proof glands must be used.
• For IS devices, Crowcon recommends the use of twisted pair cable with overall screen and
sheath. Suitable weatherproof glands must be used. IS devices must be used with a suitable Zener
Barrier or Galvanic Isolator when used in a hazardous area.
• For fire detectors, Crowcon recommends the use of twisted-pair cable, screened with an overall
protective sheath that is fireproof, for example, Pirelli FP200 or similar. Suitable weatherproof
glands must be used. The maximum acceptable loop resistance is 100ohm.
Alternative cabling techniques, such as steel conduit, may be acceptable provided that appropriate
standards are met.
The minimum acceptable supply voltage measured at the detector and the maximum current drawn by
that detector is different for each device. Please refer to the relevant Installation, Operating and
Maintenance Instructions provided with each detector to calculate the maximum cable distances
allowed for different cable types. The maximum cable distance allowed is dependent upon the
installation, for example, whether Zener Barriers or Galvanic Isolators are required (as for IS devices)
or not.
When calculating the maximum cable length for a detector, take the minimum supply voltage at the
Quad Channel Input Module as 18V at 350mA for a 3-wire detector head, 19.8V at 25.8mA for a 2-
wire head. Typical cable characteristics are shown in Table 5.
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