Operating Principle Of The Pulse Generator - Siemens SIMATIC S7-1200 Function Manual

9.4.4.3

Operating principle of the pulse generator

The function PULSEGEN transforms the analog manipulated value LmnN through pulse
width module into an impulse sequence with the period duration PER_TM. PULSEGEN is
switched on with PULSE_ON = TRUE and is processed in the cycle CYCLE_P.
A manipulated value of LmnN = 30% and 10 PULSEGEN calls per PER_TM therefore
means:
● TRUE at output QPULSE for the first three PULSEGEN calls
(30% of 10 calls)
● FALSE at output QPULSE for seven further PULSEGEN calls
(70% of 10 calls)
The duration of a pulse per pulse repetition period is proportional to the manipulated variable
and is calculated as follows:
Pulse duration = PER_TM * LmnN /100
By suppressing the minimum pulse or break time, the characteristic curve of the conversion
develops "knees" in the start and end regions.
PID control
Function Manual, 03/2017, A5E35300227-AC
Instructions
9.4 PID basic functions
481