Multifunctional input, digital input - Basic Documentation - RDF302 - RDF302.B - RDF302/VB

Semi-flush mount room thermostats with RS485 Modbus communications RDF302, RDF302.B, RDF302/VB

Product Family
Product Group
Thermostats (temperature controller with sensor)
Content Language
English
Content Type
Technical Documentation > Basic Documentation
Product Version
Status
Valid
Date
2022-06-17
Document No
CE1P3079en
Download ID
A6V10350339
Stock No.
S55770-T238
S55770-T416
S55770-T428
Product No.
RDF302
RDF302.B
RDF302/VB

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.

Modbus
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

Modbus
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

Modbus
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

Modbus
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

Modbus
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.
(Alarm x, with x = 1 for X1, x = 2 for X2).

Note: Fault displays have no impact on the thermostat's operation. They merely represent a visual signal.

DI

Modbus
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

Modbus
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.