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Much of the field wiring on any system is routed from the SPS to remote devices and appliances.
Which inputs on the SPS are used depends on the type of communications being used. This section
describes how the SPS connects to IDNet initiating devices. The RPS does not support IDNet
circuits.
Up to 250 IDNet initiating devices are supported on the SPS IDNet channel. The SPS supports both
Class A and Class B wiring.
Class A wiring allows IDNet appliances to communicate with the SPS even in the event of an open
circuit somewhere in the loop. Class A wiring requires that two wires are routed from the SPS to
each IDNet appliance, and then back again to the SPS.
Class B wiring allows “T” tapping, and therefore requires less wiring distance per installation than
Class A. Additionally, Class B wiring does not require end-of-line resistors, because each IDNet
appliance communicates directly to the SPS.
Review these guidelines before wiring the SPS for IDNet.
All wiring is 18 AWG (0.8231 mm
2
) (minimum) to 12 AWG (3.309 mm
2
) (maximum).
All wiring is supervised and power-limited.
IDNet communications power is 36.25 V (maximum) at 0.5 A, 3333 BPS.
All wiring that leaves the building requires overvoltage protection. Install module
2081-9044 (3 A) or 2081-9028 (1/4 A) inside a UL-Listed electrical box wherever wire
enters or exits the building. A maximum of four 2081-9044 Modules may be connected to
one channel. When using the 2081-9044, the maximum alarm current is reduced to
1/4 A for that part of the circuit downstream of the module. Refer to 574-805 for
installation instructions of 2081-9028 modules or to 574-832 for installation instructions of
2081-9044 modules.
For Style 4 operation:
The maximum distance
“T” taps are allowed.
Maximum allowed line-to-line capacitance (“+” to “-” terminals) is 0.58 µF to any
device is 2,500 feet (762 m). For applications with shielded wire, ensure that the total
capacitance from line to line plus the shield to either line is less than 0.58 µF (reduce
the cable length if capacitance exceeds 0.58 µF).
Maximum allowable wire load is 10,000 feet total or 0.58 µF line-to-line capacitance.
Maximum distance to any device is 2500 ft (126-250 devices) or 4000 feet (up to 125
devices).
For Style 6, the maximum loop distance is 2,500 feet (762 m). “T” taps are not allowed.
Use the supplied ferrite beads as shown in each figure. Loop wires once through the
supplied ferrite bead(s) as shown below:
Figure 9. The Ferrite Bead for IDNet Circuits
Continued on next page
IDNet Field Wiring (SPS only)
Overview
General Information
Guidelines
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