Pulse Width Modulation (Pwm) - ABB SA/S 12.16.6.1 Product Manual

®
ABB i-bus KNX
4.3.3 Pulse width modulation
(PWM)
156 2CDC 505 056 D0207 | SA/S
Planning and application
Should the SA/S receive a 1 byte control value as an input signal, it can use
this value with the parameterised cycle time and undertake a PWM
calculation.
With PWM control, the received control value (0...100 %) calculated in the
control algorithm is converted to a pulse width modulation.
The conversion is based on a constant cycle time. If the SA/S, for example,
receives a control value of 20 %, then for a cycle time of 15 minutes the
valve will be opened for three minutes (20 % of 15 minutes) and closed for
12 minutes (80 % of 15 minutes).
Calculated
control value
100 %
80 %
60 %
40 %
10 %
20 %
0 %
0
Control value
transmitted
1
0
0
Input
10 % on (1.5 min)
90 % off (13.5 min)
60 %
20 %
15 30
15 30
20 % on (3 min) 60 % on (9 min)
80 % off (12 min) 40 % off (6 min)
40 %
45 60
t in minutes
45 60
t in minutes
40 % on (6 min)
60 % off (9 min)