Gate Control ?

Hello kesimal,

I suggestion is to do the follow:

• read your value of the sensors and evaluate your result
• check if you need to open or close your gate
• set a impulse for e.g. 2 s to move your gate in the right direction (e.g a movement of 1 cm)
• start a timer e.g. 1 min or more
• after the timer is ended read your value and evaluate them again (ceck reaction)
• and so far

For this very slow processes I wouldn't use a PID like CONT_C 

For the output I would use a "normal" out and not a PWM.

Of course you can use a PWM e.g. with a PID 3 Step, but I would start with the "easy" solution.
If you have enough values to configure exactly your PID then can you change to the PID 3 Step.

regards
CaOd

Dear Mr.Kesimal;

I want to thank to Mr. Caod for valueable suggesiton.

For a similar application I made a project. 

my project was to locate a pneumatic cylinder at a desired point. Due to characteristic of air pneumatic cylinder can be used only at 0 or 1 position.

My project was similar to your application.

I used before PID 3 Step function with PWM. But then I used PID compact function, also I used only one PID.

I made an error value. Error valvue was calculated by subtracting process value from set point. that means it gave a signal "- minus" or "+plus" and according to signal I controlled output of solenoid valves. Also when error was "-" I controlled one coil of valve, when error was"+"I controlled the other coil of valve.

I added my PID application as pdf at the attachment.

I am not sure this can be useful or not.