The thermostat has 2 multifunctional inputs X1 and X2. RDF302.B does not have inputs X1 and X2.
An NTC type sensor like the QAH11.1 (AI, analog input) or a switch (DI, digital input) can be connected to the input terminals. The functionality of the inputs can be configured via parameters P38 + P39 for X1 and P40 + P41 for X2.
X1 input
X2 input
The current temperature or state of the inputs X1/X2 is available on Modbus for monitoring purposes.
The parameters can be set to the following values:
| # | Function of input | Description | Type X1/X2 |
|---|---|---|---|
| 0 | Not used | No function. | -- |
| 1 | External / return air temperature | Sensor input for external room temperature sensor or return air temperature sensor to acquire the current room temperature, or floor heating temperature sensor to limit the heating output. Note: The room temperature is acquired by the built-in sensor if the floor temperature limitation function is enabled via parameter P51. |
AI |
Heating / cooling changeover
| # | Function of input | Description | Type X1/X2 |
|---|---|---|---|
| 2 | Heating / cooling changeover | Sensor input for “Automatic heating / cooling changeover” function. A switch can also be connected rather than a sensor (switch closed = cooling, see section 3.5). Heating / cooling changeover is also possible via Modbus. In this case, the function must not be assigned to any local input X1, X2. See also section 3.5. Diagnostic value 0 ˚C is displayed for closed contact / 100 ˚C for open contact, if a switch is connected. |
AI / DI |
Window state
| # | Function of input | Description | Type X1/X2 |
|---|---|---|---|
| 3 | Operating mode switchover | Digital input to switch over the operating mode to Economy. If the operating mode switchover contact is active, user operations are ineffective and “OFF” is displayed. Operating mode switchover is also possible via Modbus. In this case, the function must not be assigned to any local input X1, X2. See also section 3.2. |
DI |
| 4 | Dew point monitor | Digital input for a dew point sensor to detect condensation. Cooling is stopped if condensation occurs. | DI |
Enable electric heater
| # | Function of input | Description |
Type X1/X2 |
|---|---|---|---|
| 5 | Enable electric heater | Digital input to enable / disable the electric heater via remote control. Enable electric heater is also possible via Modbus. In this case, the function must not be assigned to any local input X1, X2. See also section 3.6. |
DI |
Fault information
| # | Function of input | Description | Type X1/X2 |
|---|---|---|---|
| 6 | Fault | Digital input to signal an external fault (example: dirty air filter). If the input is active, “ALx” is displayed and a fault is sent on the Modbus. See also section 3.11.1. Note: Fault displays have no impact on the thermostat's operation. They merely represent a visual signal. |
DI |
X1 input, X2 input
| # | Function of input | Description | Type X1/X2 |
|---|---|---|---|
| 7 | Monitor input (Digital) | Digital input to monitor the state of an external switch via Modbus. | DI |
X1 input, X2 input
| # | Function of input | Description | Type X1/X2 |
|---|---|---|---|
| 8 | Monitor input (Temperature) | Sensor input to monitor the state of an external sensor (e.g. QAH11.1) via Modbus. | AI |
Operational action can be changed between normally open (NO) and normally closed (NC) via parameter P39, P41
Each input X1 or X2 must be configured with a different function (1…5). Exception: 1 or 2 inputs can be configured as fault (6) or monitor input (7,8)
X1 is factory-set to “Operating mode switchover” (3), X2 to “External sensor” (1)
If a multifunctional input is configured as analog: "Err" will be displayed when the output is out of range (0...49 °C), open or shorted.
For more detailed information, refer to section 3.4 “Applications”.
Installation notes:
For inputs X1 and X2, one physical switch can be used for up to 20 thermostats (parallel connection).
For sensors on inputs X1, X2, or D1, the cable length is max. 80 m.