Communication bus and supply power wiring guidelines - Verasys - Field Device - VEC100

Verasys Equipment Controller (VEC) Installation Guide

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Table 1 provides information about the functions, ratings, and requirements for the communication bus and supply power terminals. The table also provides guidelines for wire sizes, cable types, and cable lengths for when you wire the controller's communication buses and supply power.

In addition to the guidelines in Table 1, observe these guidelines when wiring a sensor bus or zone bus, and the 24 VAC supply power:

  • Run all low-voltage wiring and cables separate from high-voltage wiring.
  • All sensor bus and zone bus cables, regardless of wire size, should be twisted, insulated, stranded copper wire.
  • Shielded cable is strongly recommended for all sensor bus and zone bus cables.
  • Refer to the Verasys BACnet MS/TP Communications Technical Bulletin (LIT-12012362) for detailed information regarding wire size and cable length requirements for the sensor bus and zone bus.
Table 1. Communication bus and supply power terminal blocks, functions, ratings, requirements, and cables
Terminal Block/Port Label Terminal Labels Function, Electrical Ratings/Requirements Recommended Cable Type


Zone Bus Communications 0.6 mm (22 AWG) stranded, 3-wire twisted, shielded cable recommended
COM Signal Reference (Common) for Bus communications
SHD Isolated terminal (optional shield drain connection)


SENSOR BUS RJ-12 6-Position Modular Connector provides: Sensor Bus Communications

Sensor Bus Signal Reference and 15 VDC Common

15 VDC, 71.5 Ω at 4 W, Power for Bluetooth Commissioning Converter or ZFR1811 Wireless Router

24 AWG 3-pair CAT3 cable <30.5 m (100 ft)


Sensor Bus Communications 0.6 mm (22 AWG) stranded, 4-wire (2 twisted-pairs), shielded cable recommended.
Note: The + and - wire are one twisted-pair, and the COM and PWR are the second twisted pair of wires.
COM Sensor Bus Signal Reference and 15 VDC Common
PWR 15 VDC Supply Power for Devices on the Sensor Bus (Maximum total current draw for Sensor Bus is 240 mA.)
24~ INPUT HOT 24 VAC Power Supply - Hot

Supplies 20–30 VAC (Nominal 24 VAC)

0.8 mm to 1.0 mm (20 AWG to 18 AWG), 2-wire
COM 24 VAC Power Supply Common (Isolated from all other Common terminals on controller)

20 VA at 24 VAC nominal