Correcting physical Bus problems - Metasys - LIT-12011034 - General System Information - Metasys System - Release 11.0

MS/TP Communications Bus Technical Bulletin

Product name
Metasys System
Document type
Technical Bulletin
Document number
Release 11.0
Revision date

The MS/TP bus is subject to a number of physical factors that can affect performance. Consider the following common physical attributes:

  • Check wires.

    • Verify proper wire gauge, connections, polarity, and lengths.

    • Look for opens and shorts.

  • Check terminations.

    • Verify that EOL terminations are only at the ends of daisy chains.

  • Check addresses.

    • Check for duplicate addresses.

    • Verify that the address range is sequential.

  • Check for and eliminate T-Taps (wire configurations that create a T shape) and star configurations.

  • Check for consistent baud rates.

  • Check for sources of interference.

Note: Use the Field Inspection Tool (MS-FIT100-0) to test and troubleshoot the MS/TP bus that connects supervisory controllers and field controllers to field point interfaces.