Siemens RDB160BN - Additional Functions: Changeover and Sensors

Applications
Additional functions
4
12
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Possible output combinations
2-pipe
2-pipe with electric
heater
4-pipe
Fan
1/2/3-speed
DC 0…10 V
1/2/3-speed
DC 0…10 V
1/2/3-speed
DC 0…10 V
Output #1
On/Off, PWM, 3-position,
DC 0…10 V
On/Off, PWM, DC 0…10 V
On/Off,
PWM,
DC 0…10 V
On/Off
, PWM
DC 0…10 V
Output #2
n.a.
On/Off
On/Off, PWM
4.2 Additional functions
Heating / cooling changeover via BACnet
Heating / cooling changeover is a function that enables 2-pipe systems to use
the same pipe for both heating and cooling control. Heating control is normally
required in winter when the outside temperatures are low, while cooling control
is normally required in summer.
The heating / cooling changeover signal can be received via BACnet.
In case there is no changeover signal, e.g. due to problems with data
communication or power failure, the thermostat operates in the last valid
operating mode (heating or cooling).
Automatic heating / cooling changeover via changeover sensor
If a cable temperature sensor (QAP2012.150) is connected to the input terminal
UI, and if parameter P14 is set to 2, the thermostat changes between heating
and cooling mode according to the water temperature measured by the
changeover sensor:
● If the water temperature is above 28 °C, the thermostat changes over to
heating mode and stays in heating mode until the temperature falls below
16 °C.
● If the water temperature is below 16 °C, the thermostat changes over to
cooling mode and stays in cooling mode until the temperature rises above
28 °C.
The water temperature is defined via BACnet object.
Changeover switch
The sensor QAP2012.150 or any other PT1000 cable temperature sensor for
automatic heating / cooling changeover can be replaced by an external switch
for manual, remote changeover by setting P14 to 1.
● Contact open: Heating mode
● Contact closed: Cooling mode
The sensor or switch can be connected to input terminal U1. See also chapter
'Multifunctional input, digital input [➙ 24]'.
T
T °C
M
UI
M
UI