Controls Window

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Navigation: User Guide ➔ Windows ➔ Controls Window

PID Controller Controls Window Controls

Introduction

The main functions of this Controls Window are to list, tune and trend all the PID controllers used in the project. The Controls window is saved with extension trc. In Build139 and later, this file will be saved to the \DocsTrend subfolder.

When a new Controls page is created; all PID controllers used in the project will be added to this Controls window automatically.

  • The controllers information will appear on the list in the order they were created.
  • If a controller was deleted/added in the model's Access Window, the Trend Window can be updated by using the Trend | Reconnect all option.

For Build137 and earlier, this window was called Trend Window With Controller.

Open a New Controls Window

To open a new Controls window, use one of the following commands:

  • If the 'Control' menu is active (click on any Controls window), click on Control - New Control Window.
  • Right click on 'Trends' in the Explorer Window (if this is not already open, click on View - Explorer) and select 'New Controls Window'.
  • With a project open, use one of the following commands:
New Doc Control.png

Each of these methods will open a new Controls Window 'Controls_x.trc.'

Notes:

  1. This command is only available if a SysCAD project is open.
  2. This command is not available if SysCAD is solving or running.
  3. For Build 137 and earlier, please select "Trend" "With Controllers".

The Tuning Parameters

The controls window is basically divided into three sections, the first and third sections are the same as the normal trend window, being the Trend Line View and Trend List View respectively. See Trend Window (Normal). The second section is unique to the controls window, listing all the necessary tuning parameters for the controllers.

An example of the Controls window is shown below:

TrendWithControl1.png

Notes on Autotune:

  1. Only one PID loop can be auto tuned at any one time. The user may then repeat the exercise to tune other controllers in the project.
  2. As with any operating plants, some controllers may need more fine tuning depending on the interaction with other controllers. In most cases, it is best to hand-tune some of the more sensitive controllers first to get the plant under control and use the auto tune for optimisation.
Tuning Options
  • AutoTune Button Small 1.png : This turns on the Auto Tune function where SysCAD analyses the behaviour of the control loop in view using the user specified/default settings and optimises the PID. When the controller is tuned, it overwrites the user specified Gain, PB, Ic and Dc values with the optimum values derived from the tuning exercise.
  • TuneWithHold Button Small 2.png: This allows the user to tune a loop while holding other loops steady, only works in conjunction with AutoTune.
  • HoldAll : Holds all control loops steady.
Plant Value
  • Plant Gain : The total gain
  • Plant Delay
  • Plant Period
Button Small 3.png
Turning PID Values
and Tuning
Parameters
  • PID Gain : This is the gain for the PID loop in view, denoted by the blue magnifying glass icon User Guide image076.jpg.
  • PID Integral (Ic) : This is the integral for the PID loop in view, denoted by the blue magnifying glass icon User Guide image076.jpg.
  • PID Derivative (Dc) : This is the derivative for the PID loop in view, denoted by the blue magnifying glass icon User Guide image076.jpg.
  • Min Settle Count : The minimum number of iterations used to test for loop steadiness.
  • Max Settle Count : The maximum number of iterations used to test for loop steadiness.
  • TestDelta : This is the step size used while analysing the behaviour of the loop. Eg, 0.01 is 1% change of output value.
  • MaxPBDeRate : This is the factor used to change the value of the PB while Auto Tuning.
Button Small 4.png
Turning triggers
and status
display
  • Clicking on User Guide image077.jpg under State enables the user to view the tuning parameters for the selected loop. Only one PID loop's parameters can be viewed at a time. (See parameters PID gain, Ic, Dc above.)
  • Clicking on User Guide image079.jpg under State toggles the loop's output to be auto/manual. Colour code: green - auto; yellow - manual; red - all controller for the PID unit are switched off, not present or controller is switched off individually.
  • The symbol User Guide image081.jpg will appear under State when the loop is on hold.
  • Clicking on User Guide image083.jpg under State toggles the loop's tune option on/off.
  • The symbols User Guide image085.jpg & User Guide image087.jpg will appear under State when the loop is being auto-tuned.
Trending
  • The set point (value), measured (process variable value) and output (value) can be trended. eg:
User Guide image088.gif

How to Auto Tune a Single Loop

  1. Add a Controls Window if the project doesn't already have one. (One per project only.)
  2. Enable the AutoTune Button Small 1.png option which is located at in the top left corner of the Controls Window
  3. Make sure all PID controllers have the TuneWithHold Button Small 2.png option selected
  4. If the controller to be tuned is currently converged, force it to change output by either introducing a disturbance/step change to a variable which will affect its measured value or simply change the controller's setpoint
  5. For the PID controller to be tuned, left click on the relevant AutoTune1.png under the State heading Button Small 4.png, if the User Guide image083.jpg is not present, right click under the State Heading next to the PID of interest and choose Tune.
  6. Solve or Run the project Runbutton.png, this will start the PID tuning
  7. All the other controller's outputs will be held constant while the controller is being tuned, shown by the symbol User Guide image081.jpg AutoTune2.png
  8. While the controller is being tuned, the User Guide image085.jpg & User Guide image087.jpg symbols will be shown next to it and the controller output will be held constant
  9. When the tuning has been completed, the controller settings (Gain, Integral, Derivative) will be changed to new values and all controllers will be allowed to control normally
    AutoTune3.png