Sensors And Changeover Functions - Siemens RDG20 KN Series Basic Documentation

Functions
4
Additional functions

4.6.1 Sensors and changeover functions

Heating/cooling
changeover via bus (KNX)
Heating/cooling
changeover
Automatic heating/cooling
changeover via
changeover sensor
Note
Changeover switch (P150,
P153, P155)
Note
48 | 180
The heating/cooling changeover information is received via bus. This is only
possible if the control sequence is set to automatic heating/cooling changeover
(P001 = 2) and no local input (X1, X2, U1) is assigned to this function.
In required information is unavailable (e.g., due to data communication issues,
power failure, etc.), the thermostat operates in the last valid room operating mode
(heating or cooling).
If a cable temperature sensor (LG-Ni1000 or NTC 3k) is connected to X1/X2/U1,
and P150/P153/P155 is set to 2, the water temperature acquired by the
changeover sensor is used to change over from heating to cooling mode, or vice
versa.
●
When the water temperature is above 28 ° C (adjustable via P060), the
thermostat changes over to heating mode and remains in heating mode until
the temperature drops below 16 ° C (adjustable via P059).
●
When the water temperature is below 16 ° C (P059), the thermostat changes
over to cooling mode and remains in cooling mode until the temperature
exceeds 28 ° C (P060).
●
If the water temperature is between the 2 changeover points immediately after
power-up (within hysteresis), the thermostat starts in the previous mode.
The water temperature is acquired and the operating state is updated accordingly.
M Operating mode
T Water temperature
w
The setting range is 5 ° C...P060-2 K for P059 and P059+2 K... 40 ° C for P060.
When P001 = 2 (H/C changeover auto) is selected, an NTC 3k or LG-Ni1000 cable
temperature sensor for automatic heating/cooling changeover or one external
switch for manual or remote changeover can be used to switch the equipment
between heating and cooling:
The sensor or switch can be connected to input terminal X2, X1 or U1 based on
the commissioning of the inputs (P150 (X1), P153 (X2), P155 (U1) = 2).
See also Multifunctional input, digital input [➙ 112].
When using an external switch for changeover, the operating action is configured
via P150, P153 or P155 = 2.
Cooling mode
Heating mode
Normally open:
Contact open ⇨ Heating mode
Contact closed ⇨ cooling mode
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