Specifications

EOL Terminator Module
The MS-BACEOL-0 RS485 EOL Terminator provides EOL termination on FC bus segments when the device
connected at the end of a bus segment does not have integral EOL termination capability.
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.
An EOL terminator is required in all Metasys MS/TP applications wherever a terminating device on an FC bus
segment does not have integral EOL termination (for example, TEC26xx Series thermostats).
The EOL terminator is designed for FC buses and provides better bus performance than the integral EOL termination
on third-party devices. An EOL is recommended wherever a third-party device terminates an FC bus segment. If
the EOL terminator is connected to a third-party device that has integral EOL termination, the integral EOL termination
on the third-party device must be disabled.
TEC26xx Series Thermostats and Third-Party MS/TP Devices
TEC26xx Series thermostats and third-party MS/TP devices generate more data traffic than Metasys MS/TP devices.
Increased data traffic reduces FC bus performance and reduces the number of devices that can be connected to
the bus. When any of these devices are connected on an FC bus, different device and cable length limits apply to
the bus and bus segments.
If one or more TEC26xx Series thermostat and third-party BACnet® MS/TP device are connected on an FC bus,
the supported maximum device counts, bus segments, and bus length are as follows:
• 64 devices total per FC bus (maximum)
• 3 bus segments per FC bus (maximum)
• 32 devices per bus segment (maximum, not to exceed 64 devices total on FC bus)
• 1,220 m (4,000 ft) maximum per bus segment (using 22 AWG stranded, 3-wire twisted, shielded cable)
• 3,660 m (12,000 ft) maximum per FC bus (using 22 AWG stranded, 3-wire twisted, shielded cable)
TEC26xx Series thermostats and third-party MS/TP devices also have different EOL termination requirements. When
a TEC26xx thermostat is at the end of a bus segment, an EOL Terminator must be wired to the FC bus terminals
on the TEC26xx thermostat. Third-party devices should not be connected to the end of a bus segment unless the
third-party device’s EOL termination capability is disabled and an EOL Terminator is wired to the bus terminations
at the third-party device.
26MS/TP Communications Bus Technical Bulletin