Application

Sequence of Operation
Fail Mode Operation
10
Siemens Industry, Inc. Application Note, App 2033 140-1023
2015-08-07
At the end of a calibration sequence, CAL AIR automatically returns to NO. A status of
NO indicates that the controller is not in a calibration sequence.
The Autozero Module is enabled when it is wired to DO 6 and CAL MODULE is set to
YES.
Fail Mode Operation
If the air velocity sensor fails, the controller determines the status of FAIL MODE and
positions the damper accordingly. If FAIL MODE = OPEN and the velocity sensor fails,
the damper will open. If FAIL MODE = CLOSED (the default) and the velocity sensor
fails, the damper will close.
If the room temperature sensor fails, the controller holds the last known temperature
value.
Application Notes
 If FLOW is oscillating while FLOW STPT is constant, then the flow loop requires
tuning.
 The controller, as shipped from the factory, keeps all associated equipment OFF.
 Spare DOs can be used as auxiliary points that are controlled by the field panel
after being defined in the field panel’s database. The combination of DO 3 and DO
4 may be used as auxiliary motor points. If using this pair of spare DOs to control a
motor, you must unbundle MTR2 COMD and set MTR SETUP.
For more information, contact your local Siemens Industry representative.