Daikin R-32 rooftop Series, Operation Manual

Page: 25 / 40

Translation from original instructions
Packaged Rooftop
25
We reserve the right to make changes without any prior notice.
UATYA
4P645203-1
Temperature monitoring with Cascade control
If parameter “ST11” is set to “1”, “Cascade” control is enabled.
This function fulfils the system demand and keeps the air temperature in the delivery line within comfort values.
For this purpose, a virtual setpoint is calculated from the stored setpoint, as corrected with the air temperature in the
return line.
The setpoint is corrected dynamically as the air temperature changes in the delivery line.
The parameters involved in cascade temperature control are shown in the table.
The values of the parameters are representative. In specific cases, different values can be set.
Parameter Value UM Description
ST42 24.0 °C Cascade control - Unit setpoint
STH46 0.5 °C Mechanical heating - Cascade control - Mode switching offset
STH47 4.0 °C Mechanical heating - Cascade control - Operating differential
STH49 30.0 °C Mechanical heating - Cascade control - Max. air setpoint in delivery line
The graph below illustrates cascade control.
Spd °C
STH49
STH46 Tra °C STH47
ST42
ST42
AOC Fig. 7 Change of air setpoint in delivery line with “cascade” control in heating mode
In addition to the parameters listed in the table, the abbreviations in the graph are:
- Spd = air setpoint in delivery line;
- Tra = air temperature in return line;
- AOC = automatic mode switching.
If the air temperature in the return line is lower than the difference between the setpoints in parameters “ST42” -
“STH46”, the value of the air setpoint in the delivery line is increased gradually from the value in parameter “ST42” to
the value in parameter “STH49”, within the differential set in parameter “STH47”.