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Application

ManualsBrandsSiemens ManualsRoom controlsRoom Condition Monitor, RPM series
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Sequence of Operation
Application Notes
30
Siemens Industry, Inc.
Application Note, Application 6759
Discharge Temperature Sensor – Temperature control is lost and BTU calculations
cease if the discharge temperature analog input point, DISCH TEMP fails. This is
because the temperature loop stops updating and the discharge loop stops operating.
Application Notes
Supply Only - Operating Without a General Exhaust Box
This application can operate without a general exhaust box. If a general exhaust box is
not being controlled, set TRACK METHOD to FLOW and set the following points:
TRACK MODE to 3.
– Without a fume hood attached, use a value of 3 = ETS (exhaust tracks supply)
Flow Tracking, should be used for both the occupied and unoccupied modes.
– With a fume hood attached, use a value of 0 = STE (supply tracks exhaust)
Flow Tracking, should be used for both the occupied and unoccupied modes.
GEX FLO COEF to 0.
When GEX FLO COEF equals 0, GEX AIR VOL will always read 0, but will never
display as Failed.
OCC GEX MIN and UOC GEX MIN to 0.
If these two points are not set to 0, GEX AIR VOL— will read 0 since GEX FLO
COEF was set to 0—will be less than the general exhaust box minimum, resulting
in a false ventilation alarm.
OCC GEX MAX and UOC GEX MAX left at default or a higher value.
These two points should be set to the highest value: 1) default or 2) OCC SUP
MAX / UOC SUP MAX – small values will result in the supply box not being able to
reach higher flow setpoints.
The application varies the supply airflow as the fume hood flow changes, in order to
maintain the proper room pressurization. The supply airflow is not varied for cooling
purposes; all temperature control is done by the reheat valve.
Because of this, START should be set to 100 to allow the reheat valve to be controlled
by the full range of TEMP LOOPOUT and to prevent the room temperature PID Loop
from winding up.
General Exhaust Only - Operating Without a Supply Box
BTU compensation in Application 6759 will not function without supply airflow. Use
Application 6753.
Wiring Diagrams
Offboard Air Module Wiring.