Daikin MicroTech II User Manual

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desCrIptIon of operatIon
Proportional Integral (PI) Control Loops
The MicroTech II UVC uses PI-loop control for heating, cooling and ventilation processes
within the unit ventilator. Numerous PI algorithms can be used depending upon the unit
ventilator conguration. The UVC uses “single” and “cascading” PI loops where needed.
Table 16: PI loop list
PI loops PI loop type Set point
Feedback (controlled
variable)
Output
PI-1 Space Temperature
Cascading
Effective Heating or Cooling Temperature
Set point
Space Temperature
Calculated Discharge Air Tem-
perature Setpoint Output
PI-2 Primary Cooling (Economizer)
Calculated Discharge Air Temperature
Setpoint Output
Discharge Air Temperature Position the OA Damper
PI-4 Primary Heating
Calculated Discharge Air Temperature
Setpoint Output
Discharge Air Temperature Operate Electric Heat
PI-6 CO
2
(optional) Single Effective CO
2
Setpoint Space CO
2
Position the OA Damper
PI-7 Low Limit Single
Calculated Discharge Air Temperature
Setpoint
Discharge Air Temperature Position the OA Damper
Figure 16: PI loop graphic for CO
2
Discharge Air Temperature Control
The UVC uses two “cascading” PI loops to aid in providing very stable space tempera-
ture control. The Space Temperature PI-loop is used to calculate the Discharge Air
Temperature Setpoint Output required to meet the Effective Temperature Setpoint Out-
put. A second PI-loop (Primary Cooling, Secondary Cooling, or Primary Heating) is then
activated to control the heating or cooling device required to achieve the calculated
Discharge Air Temperature Setpoint Output. The second PI loop used is independent
upon unit mode (i.e., Heat or Cool).
Figure 17: Cascading PI loop graphic 1 (primary heat)
Figure 18: Cascading PI loop graphic 2 (primary cool—economizer)

Daikin MicroTech II Specifications

General

Brand	Daikin
Model	MicroTech II
Category	Controller
Language	English