Operating Instructions

Chapter 1—Hardware
1-8 Siemens Building Technologies, Inc.
Relay Module
WARNING:
The relay module is a high voltage device.
A Terminal Equipment Controller relay module (Figure 1-6) is used in conjunction with the
controller when the following situations are present:
ATEC digital output (DO) is used to drive electric heating coils.
Controlled load is greater than 12 VA.
Controlled load is greater than 24 Vac.
Controlled load is DC.
Controlled load is powered by a transformer other than the one powering the ATEC.
Controlled load is suspected of creating electromagnetic interference or noise in the
control signal.
Figure 1-6. Terminal Equipment Controller Relay Module (540-147) in Enclosure.
For more information about controller components and accessories, consult the Specification
Data for APOGEE™ Automation Products (144-130) or contact your local Siemens Building
Technologies representative.