Reflex function block: PWM (Pulse Width Modulation)
(Original Document)
About us
Role
This function is used to generate a fixed period periodic signal t1i with a variable duty cycle t2i/t1i.
Structure
The table below shows the block's different interfaces.
Name
Meaning
Illustration
E
Block's input.
x
Block's physical output.
x Aux
Block's internal auxiliary output (control output).
Operation
This table describes the different operating phases of the PWM function block.
Phase
Description
1
On the rising edge of input E :
  • oscillation of output x,
  • control input x Aux changes to 1.
2
On the low status of input E:
  • the oscillation of output x stops at its low status,
  • control input x Aux changes to 0.
Note: if t2i (high status of period t1i) is higher than or equal to t1i, output x continually keeps the high status.
Illustration
The illustration below shows the trend diagram of the PMW function block.
Characteristics
This table describes the characteristics of the PWM function block.
Characteristic
Value
Time Base
0.1 ms
F max
2 KHz
t1i (period)
0.1*(5 to 65535)
t2i (time on)
0.1*(2 to 65534)
Frequency and Duty Cycle
This table describes the frequency and the duty cycle range.
t1
Frequency
Step
Number of steps
Duty Cycle min
Duty Cycle max
5
2 KHz
20%
4
20%
80%
10
1 KHz
10%
9
10%
90%
100
100 Hz
1%
99
1%
99%
1000
10 Hz
0.1%
999
0.1%
99.9%
10000
1 Hz
0.01%
9999
0.01%
99.99%
65535
0.15 Hz
0.0015%
65534
0.0015%
99.9985%