Technichal Manual Heating Actuators AKH
MDT technologies GmbH •
51766 Engelskirchen
• Papiermühle 1
Tel.: +49-2263-
880 • Fax: +49
-2263-4588
• [email protected] • www.mdt.de
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Option 1:
Cycletime is larger than the adjustment time of the valves
These setting effects, that the valves are driven once completely open and once completely close
during one cycletime. So the valve go trough all possible steps during one cycletime.
The adjustment time of the valve is composed by the dead time (time which elapsesbetween
controlling the valve and opening the valve) and the real adjustment time of the valve. So the time at
wich the valve is really opened is much smaller than the controlling during one PWM cycle.
The principle of this option is shown at the diagram below:
The whole adjustment time is here about 2.5
–
3min. This is a typical adjustment time for underfloor
heatings. So the real open or real close time time is around this time smaller than the whole
controlling time. Because the adjustment time is needed for a closing and a opening process, the
room temperature is controlled precisely.
But this method can also cause larger fluctuation close to the heat source. Furthermore the valves
are more heavily loade by the relatively often driving process.
This setting is proven at slow systems, e.g. underfloor heatings.
