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3 Functions
3.1 Temperature control
The RDB160BN BACnet MS/TP room thermostat controls the room
temperature with a built-in temperature sensor, an external room temperature
sensor (QAA2012) or an external return air temperature sensor (QAP2012.150).
It maintains the setpoint temperature by sending actuator control commands to
the heating and/or cooling equipment.
The following control outputs are available:
● On/Off control (2-position)
● Modulating PI/P control with PWM output
● Modulating PI/P control with DC 0...10 V control output
● Modulating PI/P control with 3-position control output (only for 2-pipe
applications)
The switching differential or proportional band is 10 K for heating and cooling
mode, and it is set via parameter P08. The integral action time for modulating
PI control is 300 seconds. It is set via parameter P09.
Display
The display shows the current room temperature or the Comfort setpoint
temperature. Both are selectable via parameter P24. Factory setting is the
display of the current room temperature.
Heating / cooling changeover
Changeover between heating and cooling mode is automatically controlled with
a local sensor or a BACnet object.
The HEAT / COOL symbols indicate that the system currently heats or cools.
Either heating or cooling output is activated.
For detailed information about setting the control parameters refer to chapter
'Control parameters [➙ 32]'.
3.2 Operating modes
The RDB160BN BACnet MS/TP room thermostats have different operating
modes. The operating modes can be changed via On/Off button, switch over
contact or BACnet. Specific heating and cooling setpoints are assigned to each
operating mode.
Room operating mode: Preselection
The Preselection operating mode can be selected via BACnet. In Preselection
operating mode, Comfort, Standby (Economy) or OFF mode can be selected.
● If a bus command is received via BACnet for either Comfort or Standby
(Economy) mode, the symbol of the selected operating mode is displayed
(either or ˈSTANDBYˈ).
● If a bus command is received for OFF mode, only ˈOFFˈ is displayed, and all
key buttons are deactivated, except for the On/Off button.
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