Chapter 2: Installation
34 2X-A Series Installation Manual
Connecting loops
Loop guidelines
For best results, follow these guidelines when connecting loops:
• Install at least one isolator per loop (we recommend one for every 32
devices).
• Keep loop cabling away from high-voltage cables (or any other source of
interference).
• Star, stub, and T-tap configurations are not recommended.
• Install loop devices with a high current consumption as close as possible to
the control panel.
• Ensure that the loop cable complies with the cable specifications outlined in
“Recommended cables” on page 31.
• If using shielded loop cable, ensure that the shield is continuous (connected
through to each loop device).
To prevent earth loops caused by electromagnetic interference, only one
cable shield should be connected to earth, as shown in Figure 14 on page 32.
Class A loop connection
Connect Class A loops as shown in Figure 14 on page 32. Class A loops are
supervised for open and short circuits. Terminate unused Class A loops A (+) to
B (+) and A (−) to B (−).
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