Chapter 10 Built-in PID Functions
10 - 34
10.7.6 Startup using PWM
Input is done using the A/D conversion module as shown in the simulation above and the output signal is
converted to PWM to control the system using a relay module or TR module.
The following figure shows a program example of performing PID control using A/D and D/A conversion
modules.
Step 1 : The A/D conversion module channel 0 is enabled using the regular On contact and the A/D
conversion module input data are transferred to PIDRUN Loop 0 PV.
Step 7 : If the user turns the P00700 bit On, control operation of PIDRUN Loop 0 is performed.
Step 12 : If PIDRUN Loop 0 is in stop mode, the PWM On time is set to 0 and the output to OFF.
Step 17 : PIDRUN Loop 0 MV output ( 0 ~ 10000 ) is divided by 5 into ( 0 ~ 2000 ) using the regular On
contact. D00510 is used as the PWM On time and D00520, the remaining time subtracted from
2000 by D00510, is used as the PWM OFF time.
A PWM signal with a cycle of 20000 (2 sec) can be obtained using D00510 and D00520.
The corresponding output device is driven by controling the P0004A bit using the generated
PWM.
Step 34 : The scan is completed.