User Manual

LOGO! functions
4.4 Special functions list - SF
LOGO!
224 Manual, 06/2014, A5E33039675
4.4.31
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!
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 to 10.00
B: zero offset
Range of values: 10,000 to 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 to 20,000
Max:
Range of values: -20,000 to 20,000
Output Q
Q is set or reset for the proportion of each time period
according to the proportion of the standardized value
Ax to the analog value range.
Parameter T
Note the defaults of the T parameters listed in topic Time response (Page 128).
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 188) (actual value Ax – Ay)
● Analog threshold trigger (Page 183) (actual value Ax)
● Analog amplifier (Page 195) (actual value Ax)
● Analog multiplexer (Page 213) (actual value AQ)
● Analog ramp (Page 216) (actual value AQ)
● Mathematic instruction (Page 227) (actual value AQ)
● PI controller (Page 220) (actual value AQ)
● Up/down counter (Page 173) (actual value Cnt)
● Analog filter (Page 232) (actual value AQ)
● Average value (Page 237) (actual value AQ)