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  1. #1
    Join Date
    Mar 2012
    Location
    North Carolina
    Posts
    15

    Tuning Siemens loop statements

    New to tuning pid loops in insight. I know which parameters to tune, but I would like an example of where to start. Temp sensors 20 to 120f I think. Control valves 0-10vdc. Most of the statements are around 500,5,0. Is this a good place to start? What numbers would you guys use and how did you come about them? And finally a little insight on how to tune the loop. All your help is appreciated.

  2. #2
    Join Date
    Mar 2012
    Location
    North Carolina
    Posts
    15
    Can anybody help?

  3. #3
    Join Date
    Jul 2012
    Location
    Northern NY
    Posts
    121
    P of 500, I of 5 and D of 0 is a standard staring place. The type of sensors and output don't affect the loop and although they say there is a way to calculate the numbers in the MMI menu I usually just adjust them until it works the way I want

    -Jeremy

  4. #4
    Join Date
    Dec 2009
    Posts
    25
    I assign virtual points to the P, I, and if used D so I can tune the loop without re-downloading program. Become good friends with the dynamic plotter. It has helped me tune many loops as long as you are on insight and not datamate. Good luck

  5. #5
    Join Date
    Feb 2010
    Location
    california
    Posts
    14
    What version of insight are you using? Have you tried the ADAPT statement?

  6. #6
    Join Date
    Dec 2009
    Posts
    25
    I have an older 3.6 version. We have been phasing out Siemens and replacing it with Automated Logic. I have seen the new adapt statement, but cannot implement it in my facility.

  7. #7
    Join Date
    Feb 2007
    Location
    Sacramento, CA
    Posts
    62
    When I was working at Siemens I would use the following procedure.
    1. Set P to a large & probably outrageous value, I & D set to zero.
    2. Adjust P down until you get the smallest P value without hunting. You may not reach set point.
    3. Adjust I up to get the the most stable loop output without hunting.
    I found the D value didn't need to be more than 0 for most applications. I helps if you modify the loop statement to use virtual points for the P, I & D values when tuning the loop & then hard code the final values in loop statement to finish the tuning.

  8. #8
    Join Date
    Mar 2012
    Location
    North Carolina
    Posts
    15
    We have the latest version of insight 3.12. We have some programs that use adapt statements for fan speed control. I tried to use an adapt on a cooling valve loop one time and it just seemed to be very erratic.

    I will try the P 0 0 method and see how that works.

    Most of our temps stay with-in a degree high or low most of the time with about 2 or 3 overshoots per hour. It may not get any better than that. You guys tell me

  9. #9
    Join Date
    Feb 2010
    Location
    california
    Posts
    14
    Try using 3,3,9 for the tuning variable on the adapt statement. These numbers seems to be stuck in my memory from when I did it last.

  10. #10
    Join Date
    Aug 2008
    Location
    Southern U.S.
    Posts
    13
    The numbers to properly calculate for the ADAPTIVE S or M loops depend on the equipment being used and should not be guessed at. guessing can lead to a very unstable and unreliable loop. I can try to publish the tuning spread sheet on here. As well as the proper way to calculate the numbers for a PID Loop.

  11. #11
    Join Date
    Mar 2012
    Location
    North Carolina
    Posts
    15
    That would be awesome. I'll keep an eye out for it.

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