ABB SA/S 12.16.6.1 Product Manual - Planning and Application
Manual is about: Switch Actuators
of
172
ABB i-bus
®
KNX
Planning and application
SA/S | 2CDC 505 056 D0207 157
4.3.4
Pulse width modulation
– calculation
With pulse width modulation, the control is implemented by a variable mark-
space ratio.
During the time t
ON
the valve is opened, and during the time t
OFF
it is closed.
Due to t
ON
= 0.4 x t
CYC
the valve is set to about 40 % on. t
CYC
is the so-called
PWM cycle time for continuous control.
Note
Pulse width modulation leads to frequent switching of the outputs. The
limited number of switching operations with normal Switch Actuators
should be considered! The use of electronic Switch Actuators should be
the preferred method.
100 %
40 %
0 %
t
t
ON
t
OFF
t
CYC