Daikin MicroTech III Operation Manuals page 137

Cooling/Economizer
When the Unit State is Cooling or Econo the Single Zone VAV
Control PI_Loop will be set for direct acting control to modulate
the supply fan VFD to maintain the Control Temperature at
the Occupied Cooling Setpoint . As the Control Temperature
rises, the VFD speed will be increased and as the Control
Temperature falls, the VFD speed will be decreased . An
adjustable Minimum Cooling Speed and Maximum Cooling
Speed value limits the range of modulation of the VFD .
Heating
When the Unit State is Heating the Single Zone VAV Control
PI_Loop will be set to reverse acting control to modulate
the supply fan VFD to maintain the Control Temperature at
the Occupied Heating Setpoint . As the Control Temperature
falls, the VFD speed will be increased and as the Control
Temperature rises, the VFD speed will be decreased . An
adjustable Minimum Heating Speed and Maximum Heating
Speed value limits the range of modulation of the VFD
Fan Only/MinDat
When the Unit State is FanOnly or MinDat, the supply fan
speed will be held fixed at the speed the VFD was operating
upon entering the FanOnly or MinDat state . This will be either
the Minimum Cooling Speed or the Minimum Heating Speed
depending on the state the unit enters FanOnly/MinDat from
Building Static Pressure Control (BSP)
Building static pressure supply fan control is available on
100% OA units that have the Control Type set to Zone or DAC .
Building static pressure supply fan control is not available if the
Control Type set to 1ZnVAV (2) . When BSP is selected as the
SAF capacity control method, the supply fan VFD is controlled
to maintain a building static pressure input at a building static
pressure setpoint using a PI Loop .
A BSP Input parameter allows for selecting No or Yes for supply
fan building static pressure control . If BSP Input is set to No then
no monitoring or control based on BSP is possible . All menu
items related to BSP control are removed from the HMI in this
case . If BSP Input is set to Yes then the building static pressure
input is available for control and monitoring purposes .
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Carbon Dioxide Control (CO
CO supply fan control is available on 100% OA units that have
2
the Control Type set to Zone or DAC .
CO supply fan control is not available if the Control Type
2
set to 1ZnVAV . When CO
control method, the supply fan VFD is controlled based on a
CO input . The supply fan speed varies linearly between the
2
Minimum PPM Speed and the Maximum PPM Speed value
as the PPM input varies from the Minimum SAF PPM and the
Maximum SAF PPM value . A CO
selecting None, VDC or mA as the type of input for the CO
sensor in this case .
If CO Input is set to None then no monitoring or control based
2
on CO is possible . All menu items related to CO
2
scaling are removed from the HMI in this case . If CO
set to VDC then the CO
monitoring purposes and the sensor scaling parameters are in
terms of volts DC . If CO
is available for control and/or monitoring purposes and the
sensor scaling parameters are in terms of milliamps .
Airflow Control (CFM)
Airflow supply fan control is available on 100% OA units that
have the Control Type set to Zone or DAC. Airflow supply
fan control is not available if the Control Type set to 1ZnVAV .
When CFM is selected as the SAF capacity control method,
the supply fan VFD is controlled to maintain a CFM input at a
Minimum Outside Air CFM Setpoint using a PI Loop .
A CFM Input parameter allows for selecting None, VDC or mA
as the type of input for the CFM sensor in this case .
If CFM Input= is set to None then no monitoring or control based
on CFM is possible . All menu items related to CFM control and
scaling are removed from the HMI in this case . If CFM Input
is set to VDC then the CFM input is available for control and/
or monitoring purposes and the sensor scaling parameters are
in terms of volts DC . If CFM Input is set to mA then the CFM
input is available for control and/or monitoring purposes and the
sensor scaling parameters are in terms of milliamps .
137 OM 920-6 • MICROTECH UNIT CONTROLLER
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peraTor
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2
is selected as the SAF capacity
2
Input parameter allows for
2
control and
2
input is available for control and/or
2
Input is set to mA then the CO
2
' g
s uIde
2
Input is
2
input
2