Specifications

EOL Terminator Module for Remote Field Bus
An EOL terminator is required in all Metasys MS/TP applications wherever a terminating device on a Remote Field
Bus segment does not have integral EOL termination (for example, TEC26xx Series thermostats and some BACnet
IP Routers).
For Metasys devices without a built-in EOL switch, use the MS-BACEOL-0 RS485 EOL Terminator. The EOL
terminator is a compact, lightweight module wrapped in a protective cover that can be quickly installed in a variety
of ways. The EOL connects directly to the terminating device on a bus segment with the attached wire leads. The
EOL requires 24 VAC, Class 2 power supplied by the field device or other 24 VAC source.
For the Loytec Router, use the L-Term LT-04 Bus Terminator. The terminator requires no external power supply.
Refer to the Loytec website (http://www.loytec.com) for additional details.
MS/TP Bus Cable Recommendations
The MS/TP bus supports much higher baud rates than the N2 bus. Higher baud rates make the MS/TP bus less
fault tolerant and less immune to interference from inductive noise sources that may be present in the application
environment.
For the best performance on MS/TP bus applications, use 22 AWG stranded wire in a shielded cable with proper
cable shield grounding. This recommendation applies to both local and Remote Field Bus installations. Other wire
gauges and non-shielded cable may provide acceptable bus performance in many applications, especially applications
that have short cable runs and low ambient inductive noise levels.
Table 11 provides cable recommendations for MS/TP applications. The recommended FC bus and SA bus cables
are available from Belden CDT Inc. and Anixter, Inc.
Alternative cables may be used in MS/TP applications. Table 12 provides information regarding the relationship
between baud rate, wire gauge, wire length, and supported device numbers. You can also use the information
provided in Table 12 to determine if existing cable runs may be used in a retrofit or upgrade MS/TP application.
Note: In Table 11, the shielded bus and cable types are recommended; the non-shielded bus and cable types are
acceptable.
34MS/TP Communications Bus Technical Bulletin