User Manual

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Siemens RDF302 Basic documentation CE1P3079en
Smart Infrastructure 2020-12-01
# 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
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
7 Monitor input
(Digital)
Digital input to monitor the state of an external
switch via Modbus.
DI
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”.
· 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.
Enable electric heater
Fault information
X1 input, X2 input
X1 input, X2 input
Installation notes: