Technical Manual
Glass Room Temperature Controller Smart SCN-RTRGx.02
MDT technologies GmbH •
51766 Engelskirchen • Papiermühle 1
•
Germany
Phone: +49-2263-
880 • [email protected] • www.mdt.de
62
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4.4.4.3 2-step control (switching)
The following setting options are available for this (here: operating mode
“
Heating
”
):
Figure 28: Settings
–
2-step control (switching)
The following table shows the possible settings for 2-step control:
ETS-Text
Dynamic range
[Default value]
Comment
Direction of controller
▪
normal
▪
inverted
Specifies the control behaviour when
the temperature rises.
Adaptation to normally open valves
Switching hysteresis
0,5 K
–
5,0 K
[2,0 K]
Setting for upper and lower switch-on
and switch-off point
Send control value
cyclically
not active, 1 min
–
60 min
[5 min]
Setting whether and at what interval the
control value is sent cyclically
Table 65: Settings
–
2-step control (switching)
The 2-step controller is the simplest type of control. Only the two states ON or OFF are sent to the
control value.
The controller switches the control value (e.g. heating process) on when the temperature falls
below a certain reference temperature and switches it off again when the temperature exceeds a
certain reference temperature.
The switch-on and switch-off points, i.e. where the reference temperature is, depend on the
currently adjusted set point and the adjusted switching hysteresis.
The 2-step controller is used when the control value can only assume two states, e.g. an electro-
thermal valve.
Switching hysteresis
The setting of the switching hysteresis is used by the controller to calculate the switch-on and
switch-off point. This is done considering the currently valid setpoint.
Example: In the controller,
with mode “Heating”, a basic comfort value of 21°C and a hysteresis of
2K are set. In the Comfort mode, this results in an activation temperature of 20°C and a
deactivation temperature of 22°C.
When making the setting, please note that a large hysteresis leads to a large fluctuation of the
actual room temperature. However, a small hysteresis can cause the control value to be switched
on and off permanently, as the switch-on and switch-off points are close together.
