I need help with a Mitsi Q02 PLC...PID LOOP

Hi fellas,

I have a Mitsubishi Q02 PLC and i need to setup a PID loop. I have downloaded the manual from mitsubishi and used there programming example but the loop either dont work (output sits at zero) or the plc goes into error when it initiates the PIDCONT function. Any help is very much appreciated.

Thanks

OK ive narrowed down the problem but still cant get it to work. So the problem: I start the loop off and it ramps accorrdingly but when i activate the command to alter the PV input the speed stays at zero until i turn the command off. Now the programming example keeps this command ON but when i do it turns the loop off it seems. Any suggesstions.

LOL...thx for the help (looks round) LOL.

The problem is solved.....where you input the PV data i.e as per example in mitsi D611 you cant use a divide function. I.e My AI were 0-4000 the PID loop worked on a range of 0-2000 so I put a divide function in and put the result straight into the loop....but it seems it crashes the loop, so I done the divide stored it in a temp variabl and then moved it to D611 and hey presto.

To me this is really strange but it now works so WooHoo. Now onto the tuning lol.

FYI: The / (division) function implicity uses the next register to store the remainder of the calculation. Thus, your division calculation was moving your remainder into the PV data register for the loop. This one has caught me more than once.