About Setting Built-In Eol Terminations - Distech Controls ECLYPSE APEX User Manual

About Setting Built-in EOL Terminations

The APEX has built-in EOL terminations and biasing. It uses a switch located on the bottom of the
controller to enable the EOL termination and/or bias based on where it is located on a data bus (usu-
ally at the end).
If the APEX is located at the end of a data bus, set the switch to position to "END".
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If the APEX is located at the end of a data bus and the data bus requires biasing, set the switch
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position to "END / BIAS". There should be a minimum of one device (maximum of two) with biasing
on the data bus.
If the APEX is located at the middle of a data bus, set the switch position to "MID". The controllers
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located at the ends of the data bus must have their EOL terminations installed or enabled.
If a controller at the end of the data bus does not have a built-in EOL termination, then add a 120 Ohm
resistor across the device's terminals as shown at the left side of the previous figure.
Figure 92: APEX EOL switch and reset button
ECB-PTU Series Line-Powered Controllers use DIP switches (found alongside those DIP switches
used to set the MAC address) to enable the build-in EOL resistors and biasing circuitry.
ECB Series 24V-Powered Controllers have built-in EOL terminations. These Controllers use jumpers
to enable the EOL resistors and biasing circuitry.
Refer to the controller's Installation Guide for how to identify and set a controller's built-in EOL termi-
nations.
ECLYPSE APEX
BACnet MS/TP Communication Data Bus Fundamentals
END/BIAS
MID END
RESET
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