Fan Output Signals
The strategy macro provides two outputs signals for fan speed:
The variable speed control output "FanSpeedCtrlSig" will be:
The variable speed fan output signal is the maximum value between the temperature and the CO2 signals.
The fan speed command output "FanSpeedComand" will be:
Fan speed control
The fan speed control based on room/ return temperature provides a fan speed increase at high room temperature deviations.
The fan speed signal FanSpeedCtrlSig will be 0% (minimum fan speed) inside of the temperature control span RMT-03, which is a percentage of the P-Band defined by RMT-01.
For this function, it is absolute necessary to have a temperature sensor connected to the input RoomRetAirTemp of the module. The fan speed output signal FanSpeedCtrlSig can be controlled between 0…100%.
With the parameter RMT-04, the user can decide if the fan speed control shall increase for heating and/ or cooling.
Note: When the input "HVAC_Mode" is enabled (not set to 999 or not connected), the input will be used instead of parameter RMT-04.
The fan speed starts to increase for heating if the room temperature reaches the value:
start point heating = CalcRoomSP - 0,5*(RMT-01)*(RMT-03)/ 100
Where CalcRoomSP is the calculated room temperature setpoint, containing the time program value compensated by the summer compensation and the setpoint wheel of the wall module.
The fan speed will be 100% if the room temperature will be equal or lower than the:
end point heating = CalcRoomSP - 0,5*(RMT-01)
The fan speed signal FanSpeedCtrlSig will be 0% (minimum fan speed) inside of the temperature control span RMT-03, which is a percentage of the P-Band defined by RMT-01.
The fan speed starts to increase for cooling if the room temperature reaches the value:
start point cooling = CalcRoomSP + 0,5*(RMT-01)*(RMT-03)/ 100
The fan speed will be 100% if the room temperature will be equal or higher than the:
end point cooling = CalcRoomSP + 0,5*(RMT-01)
With the parameter setting RMT-04 = 3, the fan speed will increase depending on the room temperature control deviation for heating and cooling as shown in the next figure:
Note: When the input "HVAC_Mode" is enabled (not set to 999), the input will be used instead of parameter RMT-04.
The fan speed overrides can be done, connecting the "EffManSwCond" of the plant strategy macro to the fan, duct static pressure control or air flow control macros.
With this connection the following overrides can be performed:
Description |
Default value |
RMT-01: room temperature control P-band |
2 K |
RMT-02: room temperature control I-time |
0 sec |
RMT-03: span for SAT-setpoint shift |
60 % |
RMT-04: fan speed control type |
3 |
SAT-01: supply air temperature low setpoint |
14 °C |
SAT-02: supply air temperature high setpoint |
26 °C |