Only ExperTune calculates the largest possible filter for your selected tuning category. The filter is as large as possible without degrading performance significantly.
- Choose from first order, second order, Butterworth or averaging filters. Try changing the filter and PID values yourself and see immediately the effect on valve wear and loop performance.
- Use ExperTune's filter time or try what-if with your own current or new filter times. Simulation and robustness plots update instantly to reflect your filter type and size.
- Use the new PV filter to analyze the effect on valve wear analysis using the new noise simulation.
- See the entire family of PV filters for each tuning category in the PID grid.
Specify your filter address and ExperTune reads the current filter value from your controller. It is displayed next to the current PID values. After ExperTune has found the best filter for your process, click Download and the filter value is written to your controller. Supported in DDE, and OPC communication options.
If your process variable is filtered, the filter may be masking or hiding problems in the loop. Additionally, a filter could make the process much harder to control.
You can direct ExperTune's Advanced Loop Optimizer to automatically unfilter your data. With "Unfilter PV" checked, optimal PID Tuning and filter calculations are based on the true data. Even though you collected filtered data, you can also see the plot of the raw data by checking unfilter.
Two unfiltering options are available allowing you to remove the effects of PV filtering no matter where the filter is in your control system. The options are:
- Filter time is automatically read and compensated for by PID tuner. In this option the filter time is read from an address in your controller. The data is automatically unfiltered (if you select "Unfilter PV")
- Or enter the filter time used by your transmitter or control system.
Either option lets you see the result of unfiltering in the time response plot—see the raw, unfiltered data.