Host Engineering Forum

General Category => Do-more CPUs and Do-more Designer Software => Topic started by: stgislander on March 31, 2023, 06:31:44 PM

Title: PID Output Turns Off?
Post by: stgislander on March 31, 2023, 06:31:44 PM

I was doing some testing of a PID loops in my Do-more project.  I'm using the H2-DM1E CPU and two F2-02DA-2L analog output modules in bipolar mode to drive servo valves.

I discovered that when MyPID.Output reaches 100%, the analog output voltage drops from approx +2.5V to 0V.  What I find interesting is when .Output reaches 0%, the analog output holds a steady -2.5V.

Is the drop to 0V at 100% output normal, and do I need to limit the PID .Output value to 99.x%?

Title: Re: PID Output Turns Off?
Post by: stgislander on April 01, 2023, 09:40:28 AM

I found the problem.  After a little time away from the problem, I discovered that I had typed 2048 into the "Scaled Max (100%)" field in my PID controller setup.   It didn't dawn on me that was the problem until I pulled up the D2 Analog Manual.  In Chapter 9 bigger than life was a warning not to exceed 2047 when writing to the DA mobule.

Title: Re: PID Output Turns Off?
Post by: BobO on April 01, 2023, 12:13:14 PM

Great!