22 Notifier SLC Wiring Manual — P/N 51253:U9 12/3/2021
Wiring Requirements Four-Wire SLC Class A and X
2.3 Four-Wire SLC Class A and X
2.3.1 Measuring Loop Resistance
The total DC resistance of the SLC pair must not exceed:
NOTE: 35 ohms for SLM-318 (CLP-2PCB) with self-test detectors installed.
• 50 ohms for SLM-318/N16, NFS-320, NFS2-640, NFS-640, LCM-320, LEM-320, LIB-200A, and LIB-400.
NOTE: 35 ohms for current SLM-318 (CLP-2PCB) with self-test detectors installed; 23 ohms for initial release SLM-318 (CLP-
PCB) with self-test detectors installed.
• 40 ohms for AFP-100, AFP-200, AFP-300/400, LIB-200, AIM-200.
Measure DC resistance as detailed and shown below:
1. Disconnect the SLC channel B (Out) and SLC channel A (Return) at the control panel.
2. Short the SLC at the last device and measure the resistance at SLC Out. Record resistance and remove the short. Refer to Figure 2.3.
3. Short the SLC at the first device and measure the resistance at SLC return. Record resistance and remove the short. Refer to
Figure 2.3.
The maximum DC resistance of the SLC is the higher of 2 and 3.
2.3.2 Measuring Total Wire Length
The total wire length in a four-wire SLC cannot exceed the limits set forth in each system’s instruction manual. The figure below identi-
fies the output and return loops from SLC terminal on the control panel or loop module:
Branch A Branch C
SLC-mAeas2.wmf
SLC Terminal Block
Segment
Two
Segment
Five
Segment
Three
Segment
Four
Segment
One
Figure 2.2 Measuring the Total Wire Length of a Two-wire SLC
Branch B
SLC-meas5.wmf
SLC Out
SLC Return
Short Point
SLC Return
SLC Out
STEP 2
STEP 3
First Device
Last Device
Last Device
First Device
Figure 2.3 Measuring DC Resistance of a Four-Wire SLC
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