Pulse Width Modulation (Pwm) - ABB i-bus KNX FCA/S 1.1M Product Manual

ABB i-bus KNX
4.3.4.2 Pulse width modulation
(PWM)
© 2010 ABB STOTZ-KONTAKT GmbH
Planning and application
With pulse width modulation the valve is operated as with 2-point control
exclusively in the positions fully opened and fully closed. In contrast to a
2-point control, the position is not controlled via limit values, but rather by
calculated control values similar to continuous control.
The control value is fixed for a timed cycle and recalculated in the duration
for valve opening. The control value 20 % at a cycle time of 15 minutes,
for example, will be recalculated for a valve opening time of three minutes.
The control value 50 % results in a valve opening time of 7.5 minutes.
Control value
Valve position
100 %
0 %
With pulse width modulation a relatively accurate control of the temperature
can be achieved without any resulting overshoots. Simple, attractively-priced
control valves can be used. The positioning frequency of the control valve is
relatively high.
Pulse width modulation can be used with the Fan Coil Actuator in
conjunction with electromotor or electro-thermal valve drives.
Time
Time
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