Operating Mode: "Heating Actuator - ABB i-bus EIB Product Manual

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ABB i-bus EIB / KNX
3.3 Operating mode:
"Heating actuator"The
© 2004 ABB STOTZ-KONTAKT GmbH
Application and planning
"Heating actuator" function is normally used to control an electrothermal
valve drive. The output receives its control value from a room thermostat.
The electrothermal valve drive can be triggered via two-step control or pulse
width modulation. When pulse width modulation is used, the control is
carried out via a variable mark-to-space ratio. The following example clarifies
this:
100%
40%
0%
t
ON
T
CYC
Fig. 6: Pulse width modulation (example)
During t , the valve is triggered with OPEN ("ON phase"). During t
ON
valve is triggered with CLOSE ("OFF phase"). Due to t
valve is set at approx. 40%. T
continuous control.
Important: A pulse width modulation leads to frequent switching of the
outputs. Consider the limited number of switching cycles for
standard switch actuators! The use of electronic switch
actuators is preferable in each case.
t
OFF
is the so-called PWM cycle time for
CYC
t
the
OFF
= 0.4 x T , the
ON CYC
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