Glitches in Signal Causing Incorrect Event Counting or Position Measurement Hardware: Counter/Timers (TIO)>>Devices>>PCI-6601
Problem: I am doing a position measurement and am not getting the results that I am expecting. When looking at the signal from the encoder, I can see that signal is not clean and the glitches are causing an invalid measurement. What can I do to remove these glitches? Solution: Aside from using external hardware to remove these glitches, you can use the digital debouncing filters on the NI-TIO boards (660x). The counters can be set up so that the external signal passes through an external filter circuit first. Changes in the signal will only be propagated if it maintains the new state for the duration between two consecutive rising edges of the filter clock. For instance, if the filter setting is set to 500 ns, all pulse widths above 500 ns will pass and all pulse widths below 250 ns will be blocked. For more information, please refer to the filter section of the 6601/6602 manual. Related Links: Product Manuals: 6601/6602 User Manual KnowledgeBase 0TE9GNU3: Why Do I Get Error -10920 When Doing Buffered Counter Operations? Attachments:
Report Date: 05/12/2003 Last Updated: 05/13/2003 Document ID: 2XBL7NLD |
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