Siemens 125-5033 - Manual (Page 21)

Applications
Siemens Building Technologies, Inc. 13
DO3 Output Functionality
DO3 is designed to operate in two different modes. DO3 can follow the alarm status of the
controller by turning ON during alarm conditions and OFF during normal operation; or DO3
can follow the HI.LOW setpoint status of the controller by turning ON while the controller is in
LOW flow operation and OFF when the controller is in HI flow operation.
Warning and Alarm Features
The Fume Hood Controller indicates fume hood performance problems at two levels,
WARNING and ALARM. The two levels are available so different procedures can be
instituted for each condition. Both levels are indicated locally at the ODP and, if connected to
a field panel, centrally through the APOGEE alarm features.
NOTE: Central alarms only work if the field panel is specifically set up to receive and
distribute the alarm information. Consult your local Siemens Building
Technologies, Inc. representative for more information on central alarming.
Warning Operation
The Fume Hood Controller announces warning conditions at the ODP. The ODP indicates a
warning condition by illuminating the yellow LED.
If the fume hood is operating and the exhaust volume exceeds the high or low warning limit
for a period greater than the delay timer a warning condition occurs.
For more information on ODP messages, see the Fume Hood Controller Operator Display
Panel User's Card (125-1976).
Alarm Operation
The Fume Hood Controller announces alarm conditions at the ODP. The ODP indicates an
alarm condition in the following three ways:
• The red LED illuminates.
• The horn sounds.
• A text message indicating the specific alarm condition displays.
If the fume hood exhaust flow exceeds the high or low alarm limit for a period greater than
the delay timer an alarm condition occurs. The text message FLO HI or FLO LO displays.
The fume hood operator may silence the horn for the current alarm event by pressing the
Horn Silence button.