Setting Up Parameters
Master Position Filter
The master filter is designed for applications where the master encoder input requires smoothing due to low resolution or high gain. These applications include low speed masters, low resolution master encoders, and large follower to master gear ratios.
Filters inherently introduce phase shift (or delay) in the followers response to the master position, velocity and acceleration. The
The user may set the number of filter samples to be used to "smooth" the master encoder velocity. The more samples used by the filter, the smoother the master velocity signal, however the more positional delay introduced by the filter. This means that more filtering will cause more position error between master and follower. Feedforward is used in conjunction with the filter to provide accurate positioning performance while still maintaining smooth motion.
The table below can be used to best determine the proper filter settings for your application.
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| Feedforward OFF | Feedforward ON |
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| One update of phase shift | No delay, |
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| Disabled | (not velocity dependent) |
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| No Filtering |
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| No Filtering |
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# of | 4 | Small Lag (function of speed), | Poor at low speed, |
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Low Filtering | Low Filtering |
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Samples |
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8 | Medium Lag (function of speed), | Good at low speed, |
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| Medium Filtering | Medium Filtering |
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| 16 | Large Lag (function of speed), | Best at low speeds, | Smoother | Increasing Lag | ||||
| High Filtering | High Filtering | with FF Off | ||||||
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Reduced Lag
Filter parameters cannot be changed using the "Update to RAM" feature. Changes must be fully downloaded before taking effect.
The gray box in the table above denotes the default setting for the master filter parameters.
Enable Check Box
The enable check box is used to turn on or turn off the Master Position Filter. If checked, the filter is active and the user must select the number of samples used by the filter. If unchecked, the filter is not used.
Samples
Defines the number of samples used by the filter to smooth the master signal. Increasing the number of samples increases smoothness, but also increases lag. See Filter table above to select proper setting.
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