Harrington Signal Tracker T8000 - Install Manual - Manual (Page 44)

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HSI #780-0867 FireSpy Tracker Installation Manual
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Table 3-4: Wire Lengths for SLC
Units 18 AWG 16 AWG 14 AWG 12 AWG
Part number of cable referenced for ratings Belden 9571 9572 9580 9582
Resistance rating of cable ohm/kFT 6.3 4.1 2.5 1.6
Capacitance rating of cable pF/ft 22 29 27 30
Max distance, resistance candidate (worst case) ft 7937 12195 20000 31250
Max distance, resistance candidate (best case) ft 15873 24390 40000 62500
Max distance, capacitance candidate ft 22727 17241 18519 16667
Max distance (worst case load distribution) ft 7937 12195 18519 16667
Max distance (best case load distribution) ft 15873 17241 18519 16667
Allowable loop current (worst case) mA 46.30 46.30 49.71 81.52
Allowable loop current (best case) mA 46.30 63.54 92.09 144.23
Resistance-based distance calculations were performed by using Eq. C-2 with Rpanel = 8, Rdevices = 0
Loop current calculations were performed by using Eq. C-3 , with Vdrop = 5 and solving for Idraw
Table 3-5: Wire Lengths for Local RS485
Units 18 AWG 16 AWG 14 AWG 12 AWG
Part number of cable referenced for ratings Belden 9571 9572 9580 9582
Resistance rating of cable ohm/kFT 6.3 4.1 2.5 1.6
Capacitance rating of cable pF/ft 22 29 27 30
Max distance, resistance candidate (worst case) ft 7937 12195 20000 31250
Max distance, resistance candidate (best case) ft 15873 24390 40000 62500
Max distance, capacitance candidate ft 13636 10345 11111 10000
Max distance, wavelength candidate ft 25614 25614 25614 25614
Max distance (worst case load distribution) ft 7937 10345 11111 10000
Max distance (best case load distribution) ft 13636 10345 11111 10000
Many factors are involved with communication circuits. Special considerations may need to be made for any specific job,
especially if these distances are exceeded.
Resistance-based distance calculations were performed by using Eq. C-1
Wavelength candidates are based on 25% of the wavelength of the circuit’s operating frequency, 9600 baud