Pulse Width Modulator (Pwm) - Siemens LOGO! Manual

LOGO! functions
4.4 Special functions list - SF
4.4.29

Pulse Width Modulator (PWM)

Short description
The Pulse Width Modulator (PWM) instruction modulates the analog input value Ax to a
pulsed digital output signal. The pulse width is proportional to the analog value Ax.
Symbol in LOGO!
Parameter T
Note the defaults of the T parameters listed in topic Time response (Page 115).
The periodic time T can be provided by the actual value of another already-programmed
function. You can use the actual value of the following functions:
● Analog comparator (Page 165) (actual value Ax – Ay)
● Analog threshold trigger (Page 160) (actual value Ax)
● Analog amplifier (Page 173) (actual value Ax)
● Analog multiplexer (Page 194) (actual value AQ)
● Analog ramp (Page 197) (actual value AQ)
● Analog math (Page 209) (actual value AQ)
● PI controller (Page 201) (actual value AQ)
● Up/down counter (Page 151) (actual value Cnt)
Select the required function by the block number. The timebase is configurable. For
information on valid ranges and parameter defaults, refer to the On-delay (Page 123) topic.
206
Wiring Description
Input En A positive edge (0 to 1 transition) at input En enables
the PWM function block.
Input Ax Analog signal to be modulated to a pulsed digital
output signal.
Parameter A: Gain
Range of values: ± 10.00
B: Zero offset
Range of values: ± 10,000
T: Periodic time over which the digital output
is modulated
p: Number of decimals
Range of values: 0, 1, 2, 3
Min:
Range of values: ±20,000
Max:
Range of values: ±20,000
Output Q Q is set or reset for the proporition of each time peri-
od according to the proportion of the standardized
value Ax to the analog value range.
Manual, 10/2017, A5E01248535-AA
LOGO!