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.

The fan speed starts to increase for heating if the room temperature reaches the value:


start point heating = CalcRoomTmpSp - 0,5*(RMT-01)*(RMT-03)/ 100


Where CalcRoomTmpSp 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 = CalcRoomTmpSp - 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 = CalcRoomTmpSp + 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 = CalcRoomTmpSp + 0,5*(RMT-01)


With the parameter setting RMT-04 = 3, the fan speed will increase depending on the room temperature contorl deviation for heating and cooling as shown in the next figure:



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
0 = no fan speed control
1 = heating
2 = cooling
3 = heating and cooling

3

SAT-01: supply air temperature low setpoint

14 °C

SAT-02: supply air temperature high setpoint

26 °C