Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 1 UNITRONICS D erivative P I roportional ntegral 1/13

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 2 PID – What's our goal? The PID function uses system feedback to continuously control a dynamic process.PIDsystem feedback The purpose of PID control is to keep a process running as close as possible to a desired Set Point.

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 3 ON – OFF control Switches the power ON and OFF (0% - 100%) Pros: Easy to understand, easy to perform. Cons: Not precise. In some systems "waves" of over and undershoots can reach 10-20% of PV. In some fast systems is impossible of all.

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 4 What's PID? Mathematical process, which is calculating in each moment the energy need by the system to achieve the goal in the best way.

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 5 PID means: Proportional + Integral + Derivative control CV = CV (P) + CV(I) + CV(D) What's PID?

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 6 Proportional control is leading. The control can be:  P control only  PI control  PD control  Full PID control What's PID?

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 7 Proportional control A band around SP is defined – in percents of PV range. Out of proportional band CV is always 100% and no calculations are done. Proportional error is 100% on the border of PB. Proportional error is 0% at SP. P-control outputs CV(P) value that is in: Direct linear proportion to the size of the Error value.

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 8 Simple – easy to understand, easy to program even in ladder Cons: Never reach Set point! Proportional control

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 9 Integral control The integral time you set is the amount of time, as calculated by the controller, required to bring the process to Set Point. According to the delay, Integral action adds value to this, calculated by Proportional action. Integral value is accumulated with the time.

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 10 Integral action CV = CV(P) + CV(I) On set point – CV(P) = 0  CV = CV(I)

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 11 Derivative action Derivative action responds to the rate and direction of change in the Error. This means that a fast change in error causes a strong response from the controller.

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 12 PID control in Vision Functional block. Many PID loops can be controlled simultaneously. Fully independent loops. Large scale of inputs and outputs. Integrated in full system logic.

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 13 PID control in Vision Advanced control functions:  Ramp and soak.  Full step programmer.  Bumpless control.  Cascade control.

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 14 Configurating FB PID: With one scan condition (mostly Power up SB2) On subroutine, which is always scanned (recommended Main routine!) PID control in Vision

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 15 PID parameters Let's open configuration block:

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 16 Why Autotune? Each system has its own set of P, I, D and St values. Finding "manually" these parameters needs experience and time. Autotune learns the system and calculates the optimal parameters for it.

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 17 Autotune – how it works? Autotune runs ON-Off cycles According to the "wave" of overshoot, the base PID parameters are calculated. Number of cycles 1 ~ 3 is set in Autotune module. More cycles – more precise result, but longer process.

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 18 Autotune – how it works?

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 19 FB PID – Advanced functions  Pause Integral and Derivative action  Read & Force integral Error  Read Control components

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 20 PID Server PID server is ideal tool for understanding, learning and debug PID process! You can use it:  To view process.  To Log it.  To Autotune it – up op to 8 cycles. It's part of VisiLogic or independent tool. FREE Of Charge

Click to edit Master title style Click to edit Master text styles Second level Third level Fourth level Fifth level 21 UNITRONICS Thank You 21/13