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| slice:z-n [2019/04/02 15:49] – Michael Radunsky | slice:z-n [2022/07/18 17:18] (current) – external edit 127.0.0.1 |
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| ===== Ziegler-Nichols Loop Tuning ===== | ===== Ziegler-Nichols Loop Tuning ===== |
| Click here for the [[slice:qt|SLICE-QT Manual]].\\ | The Ziegler-Nichols loop tuning protocol(([[https://staff.guilan.ac.ir/staff/users/chaibakhsh/fckeditor_repo/file/documents/Optimum%20Settings%20for%20Automatic%20Controllers%20(Ziegler%20and%20Nichols,%201942).pdf|Optimum Settings for Automatic Controllers, by J.G. Zieger and N. B. Nichols]] and\\ |
| Click here for the [[slice:quick_start_qt|SLICE-QT Quick Start Guide]].\\ | [[https://en.wikipedia.org/wiki/Ziegler%E2%80%93Nichols_method|Wikipedia]])) is a simple method to establishing the loop parameter values for a PI or PID control loop. This protocol is designed to optimize the loop for disturbance rejection.\\ |
| Click here for the [[slice:qt:API|SLICE-QT API]].\\ | ==== Links ==== |
| Click here for the [[https://www.vescent.com/products/electronics/slice/slice-qt-four-channel-temperature-controller/|SLICE-QT web page]].\\ | Click here for the [[slice:qt|SLICE-QTC Manual]].\\ |
| | Click here for the [[slice:quick_start_qt|SLICE-QTC Quick Start Guide]].\\ |
| This protocol is designed to optimize the loops for disturbance rejection. | Click here for the [[slice:qt:API|SLICE-QTC API]].\\ |
| | Click here for the [[https://www.vescent.com/products/electronics/slice/slice-qt-four-channel-temperature-controller/|SLICE-QTC web page]].\\ |
| | Click here for the [[https://github.com/Vescent|Github page for SLICE-QTC GUI]].\\ |
| | Click here for the [[https://github.com/Vescent/SLICE-QT-Firmware-Upgrade|Github page for SLICE-QTC firmware revisions]].\\ |
| | Click here for a [[https://youtu.be/jCuHNOW5q8c|Video Tutorial]].\\ |
| | ==== Instructions ==== |
| <WRAP center round box 60%> | <WRAP center round box 60%> |
| | {{ :warning-sign.png?50&nolink }} | There is the possibility for the loop to go unstable at too high gain. Use caution as gain is increased. | | | {{ :warning-sign.png?50&nolink }} | There is the possibility for the loop to go unstable at too high gain. Use caution as gain is increased. | |
| - Set Proportional Gain (K<sub>P</sub>) to 0 | - Set Proportional Gain (K<sub>P</sub>) to 0 |
| - Turn off Integral and Differential portions of the loop (T<sub>I</sub> & T<sub>D</sub>, respectively) | - Turn off Integral and Differential portions of the loop (T<sub>I</sub> & T<sub>D</sub>, respectively) |
| - While monitoring the error in temperature on rolling graph, **slowly** increase K<sub>P</sub> until the error begins to oscillate | - While monitoring the error in temperature on rolling graph on the SLICE-QTC display or an [[slice:qt#front-panel_inputs_outputs|external oscilloscope]], **slowly** increase (~10% per increment) K<sub>P</sub> until the error begins to oscillate |
| - Use the {{slice:graph_scale_x.gif}} and {{slice:graph_scale_y.gif}} icons, to scale displayed response appropriately | - Use the {{slice:graph_scale_x.gif}} and {{slice:graph_scale_y.gif}} icons, to scale displayed response appropriately |
| - Use the {{slice:graph_pause.gif}} icon to pause the graph | - Use the {{slice:graph_pause.gif}} icon to pause the graph |
| - Note K<sub>P</sub> where oscillation begins, K<sub>P, cr</sub> | - Note: the pause icon only pauses the graph, not the servo control |
| | - Note K<sub>P</sub> where oscillations of increasing amplitude begin; this is K<sub>P, cr</sub>, the critical proportional gain. |
| - Use the Cursors enabled by touching the {{slice:cursors.gif}} icon to measure the period of oscillation, T<sub>cr</sub> | - Use the Cursors enabled by touching the {{slice:cursors.gif}} icon to measure the period of oscillation, T<sub>cr</sub> |
| | - You can use the two rotary knobs or touch & drag the cursors on the touch screen |
| - Use the following table to set the values of K<sub>P</sub>, T<sub>I</sub>, and T<sub>D</sub> | - Use the following table to set the values of K<sub>P</sub>, T<sub>I</sub>, and T<sub>D</sub> |
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| <WRAP center round box 60%><tabcaption Z-N |Ziegler-Nichols loop values> | <WRAP center round box 60%><tabcaption Z-N |Ziegler-Nichols loop values> |
| | **Type of Control Loop** | K<sub>P</sub> | T<sub>I</sub> | T<sub>D</sub> | | | **Type of Control Loop** | K<sub>P</sub> | T<sub>I</sub> | T<sub>D</sub> | |
| | **PI** | 0.45K<sub>P, cr</sub> | 0.83T<sub>cr</sub> | 0 | | | **PI** | 0.45•K<sub>P, cr</sub> | 0.83•T<sub>cr</sub> | 0 | |
| | **PID** | 0.6K<sub>P, cr</sub> | 0.5T<sub>cr</sub> | 0.125T<sub>cr</sub> | | | **PID** | 0.6•K<sub>P, cr</sub> | 0.5•T<sub>cr</sub> | 0.125•T<sub>cr</sub> | |
| </tabcaption></WRAP> | </tabcaption></WRAP> |
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