Reading Encoder pulses using US DIGITAL PCI4E

Hello All,
I'm new to this forum so I hope that I post the question in the correct board.
I have an encoder connected to PCI4e board.
The problem is that when trying to measure velocity I get different result using different methods:
So I want to measure the Encoder pulses frequency.
I'm trying to figure out which PCI4E function gives me this information
If anyone know please tell me.
Thanks
Gil,
Solved!
Go to Solution.

Gil,
The US Digital website provides a set of VI's for using their hardware in Labview, this is not supported hardware and we do not have access to the commands that are sent to the device as it was made by a third party vendor. However there is example code for labview which can be downloaded at (http://usdigital.com/download/43) which was found in the download section of that product support page. Keep in mind, this code was created in LabVIEW 6.1 and may have problems integrating with current versions and or may have different functions and features. This download contains many different VIs which may help you to better understand the workings of the device. Feel free to contact me at any time if you experience any more issues. I will be happy to help you. Thanks!
Frank,
National Instruments
Staff Software Project Engineer

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Measurement error in reading Encoder Pulses

I am using PCI-6601 card to read a Linear Encoder which gives 2000 pulses per mm of distance.The accuracy of the Linear encoder is 2Microns.In my application I am measuring a distance of 7mm.But the card is reading with an error of 30 to 50 Microns error.We had checked up all the factors related to mechanical and Encoder.In fact the same application was earlier working with Advantech Encoder card which has provisons to connect the A,B,A Bar,B Bar inputs from Encoder.There was an accuracy of 0 to 5Microns.But the application was replaced with NI Card because of the continuous problem of the Digital I/O Card used from Advantech.
Mail me the possible causes and also the troubleshooting procedures for correcting the above problem

Hi,
What I think is happening is there might be some noise on your signal lines. The PCI-6601 counters are capable of detecting a pulse as small as 20ns. If the Advantech card can't detect pulses at that small a resolution, it might be ignoring "noisy" pulses that shouldn't be there. Are you reading more pulses than you should be or less?
There are a couple things I might be able to suggest to clean up your signal. The counters support several different encoder modes. Try using X4 Encoders. An X4 encoder counter increments or decrements on each edge of channels A and B. Whether the counter increments or decrements depends on which channel leads the other. Each cycle results in four increments or decrements. I believe this X4 mode is more noise resi
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Another thing you might want to consider is applying a filter to the input signals (debounce or deglitch filters). Each PFI line coming from the I/O connector can be passed through a simple digital filter. The filter operates off a filter clock and a fast internal sampling clock. It samples the signal on the PFI line on each rising edge of the sampling clock. A change in the signal is propagated only if it maintains its new state for at least the duration between two consecutive rising edges of the filter clock (one filter clock period). The frequency of the filter clock determines whether a transition in the signal may propagate or not.
6601/6602 User Manual
http://digital.ni.com/manuals.nsf/webAdvsearch/DD0DBB6404BC139886256721007CF16D?OpenDocument&vid=niwc&node=132100_US
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Hi,
I am a beginner labview user, I have access to three modules, two NI9201 and one NI9401.
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Go to Solution.
Attachments:
Encoder_Spark.vi ‏40 KB
Encoder_Spark.vi ‏40 KB

Hi Nick,
I hope the attached vi will get you on track. It's just a general concept.
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Reading Encoder pulses using US DIGITAL PCI4E

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