Technical data

The state (heating or cooling) of the thermostat can be monitored with the ACS tool
(diagnostic value "Control sequence"). The last active mode is displayed when the
thermostat is in the dead zone or temperature control is disabled.
With a 2 pipe application, the control sequence state is determined by the
application mode (see section 3.6.3) and by the state of the heating / cooling
changeover signal (via local sensor or bus), or fixed according to the selected
control sequence (P01 = heating (0) / cooling (1)).
Application
mode (via bus)
State changeover / conti-
nuous heating or cooling
Control sequence state
Auto (0)
Heating
Heating
Cooling
Cooling
Heat (1), (2), (8)
Heating
Heating
Cooling
Heating
Cool (3), (5)
Heating
Cooling
Cooling
Cooling
Night purge (4),
Fan only (9)
Heating
Heating
Cooling
Cooling
With a 4-pipe, 2-pipe with electric heater, and 2-pipe with radiator application, the
control sequence state depends on the application mode and on the heating /
cooling demand.
Application
Mode (via bus)
Heating / cooling demand
Control sequence state
Auto (0)
Heating
Heating
No demand Heating / cooling depending
on last active sequence
Cooling
Cooling
Heat (1), (2), (8)
Heating
Heating
No demand
Heating
Cooling
Heating
Cool (3), (5)
Heating
Cooling
No demand
Cooling
Cooling
Cooling
Night purge (4),
Fan only (9)
No temperature control active Heating / cooling depending
on last active sequence
The value of the output as a function of the room temperature is shown in the
following diagram in case of a heating and cooling system:
0
TR
Wheat Wcool
100%
0 = Cool
1 = Heat
3171D01
Wheat = current heating setpoint
Wcool = current cooling setpoint
ACS
Heating OR cooling
Heating AND cooling
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Siemens RDF301, RDF301.50..., RDF600KN Basic documentation CE1P3171en
Building Technologies Functions 2014-05-23