Correcting physical Communication Bus problems - Verasys - LC-BYP200-0 - LC-ZEC310-0 - Field Device - BYP200 - ZEC310

Verasys ZEC310 Zone Damper and BYP200 Bypass Damper Controllers Installation Guide

Product name
Document type
Installation Guide
Part number
Document revision
Revision date

The Communication Bus is subject to a number of physical factors that can affect performance. Consider the following list of common physical problems that affect the Communications Bus:

  • Check the status LED to verify power at the controller.
  • Check wires
    • Verify that the wire is a 0.6 mm (22 AWG) three-conductor, twisted, shielded cable.
    • Verify that the shield is continuous and hard-grounded at one end.
  • Check wiring
    • Check for and eliminate T-Taps, wire configurations that create a T shape, and star configurations.
    • Ensure that the bus is wired in a daisy-chain fashion.
    • Verify that appropriate devices have three wires entering and exiting each terminal. Devices at the ends of the trunk do not have this wiring.
  • Check EOL switch settings
    • Verify that only the EOL switch at the end of the system bus is set to ON, and all other system bus EOL switches are set to OFF.
  • Check connections, polarity, and lengths
    • Verify that communications loops are less than approximately 304 m (1,000 ft) total in length.
    • If you are using one transformer to power multiple devices, verify that the device 24 VAC power connection follows the polarity of the common and 24 V terminations.
  • Check for opens and shorts
  • Check terminations
  • Check addresses
    • Check for duplicate addresses.
    • Verify that the address range is sequential.
  • Check for sources of interference
  • Check bus voltages:
    • (+) to COM must be within 2.0 VDC to 3.0 VDC
    • (-) to COM must be within 1.5 VDC to 2.54 VDC
    • (+) to (-) must be within 0.3 VDC to 1.0 VDC
Note: Values may fluctuate due to ongoing communications. This operation is normal provided that the voltage is within the defined range.