Hello,

Is it possible to set the PID to run in reverse if the input exceeds the setpoint or do i need two seperate loops for positive and negative gain?

I have tried setting bipolar values in the wizard but the loop output goes to the bottom of the range if the input exceeds the set point in a positive gain loop, or if the input is less than the set point for negative gain.

Do you have any suggestions for an efficient solution where the pid loop runs in both directions depending on whether the input is greater or smaller than the setpoint?

I am working on a printing machine tension control system using s7-200 plc, load cells, dancer rollers and yaskawa a1000 and v1000 drives.

Many thanks in advance,

S

You outputlimit is +100% and -100% ?

Sarsparilla

Hello,

Is it possible to set the PID to run in reverse if the input exceeds the setpoint or do i need two seperate loops for positive and negative gain?

I have tried setting bipolar values in the wizard but the loop output goes to the bottom of the range if the input exceeds the set point in a positive gain loop, or if the input is less than the set point for negative gain.

Do you have any suggestions for an efficient solution where the pid loop runs in both directions depending on whether the input is greater or smaller than the setpoint?

I am working on a printing machine tension control system using s7-200 plc, load cells, dancer rollers and yaskawa a1000 and v1000 drives.

Many thanks in advance,

S

 Mr.sarsparilla,

Really your requirement is confusable,

But till I know and do for forward and reverse pid, normally I change gain  - or + ,

But in 200 series you have set pid through tools/pid tune ,so you can't Chang automatic in gain value, so it is not possible for automatic reverse and forward PID,

(I HOPE ANY EXPERT HAVE STANDARD IDEA FOR YOU)

Thank you for your reply. Yes, I think I will only use P&I.

My problem is that I need negative gain when above setpoint and positive gain when below.

Thank you as well. Yes it seems that I will have to jump from one loop to another or simply switch the input around the setpoint e.g. aiw0 or (32000 - aiwo).

What I'm trying to achieve is to accelerate or decelerate a motor relative to a variable line speed according to a variable tension reading from a load cell.

Sarsparilla

Thank you for your reply. Yes, I think I will only use P&I.

My problem is that I need negative gain when above setpoint and positive gain when below.

 hi ,

try PID loop as attached image to change PID action as fwd or Rev,

viral ,