Daq 6024e + IR encoder

Hi,
I am using IR sensor to calculate the rpm of my wheel-- my problem is when I am using "low freq with one counter" initially it gives me rpm but then as I increase the rpm it gives me message that "data was overwritten before it could be read try using DMA or divide the signal before measurement" now I can not divide the signal in this method I assume-- now when I change the counter to other method like "high range or large range with with 2 ctr" it tells me immediately your signal is too slow for this type of method and increase the measurement time-- I even did that increased the time to upto 50.0 but same problem
My Vi is attached -- How should I resolve this issue. As my wheel will move from rest and will gain some rpm and then stop-- so it will go from low to high to low.
Thanks
Attachments:
counterencoder.vi ‏59 KB

Hi tmdar,
Were you able to see any changes upon changing the "samples per channel" parameter? You're right, it is possible that noise in the signal is being picked up as an event as well. Also, avoid running any unnecessary applcations on your computer while running this, or try running on a different machine to see if the results vary.
LabVIEW comes with a Filter Express VI (Express >> Analysis >> Filter) which you can experiment with to perform different types of filtering. However, since this filtering is performed after the data has been acquired, it may not help with the data acquisition issue. You may need an external filter. Before taking this step, you should verify if the problem is in fact signal noise. Since you're using one counter for "Low Frequency with 1 Counter", you can use the other counter to generate a pulse train, which you can feed as the input for your counting, to see if you can get up to a higher frequency. If this works, the problem is likely with the signal source. Otherwise, the issue would likely be the system or the code (please verify that you're using the shipping example, "Measure Dig Frequency - Low Freq 1 Ctr")
Thanks,
Lesley Y.

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Edit: spelling...
Message Edited by Siggen on 12-01-2005 07:04 AM

Hi Siggen,
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DAQ-6024Eの割り込みレベルのエラー

使用アプリケーション
NI-DAQ　6.9.3
NI-Measurement　&　Automation Explprer 2.2.0
OS　 Windows2000
Measurement & Automation ExplorerからDAQCard6024Eのテストパネルを実行すると
『デバイスは指定された1つ目の割り込みレベルにて応答がありません』とエラーが表示されます。
しかしそのエラー表示のあと　テストパネルは実行され　最新のエラーも0　と表示されています。
この状態の時、DAQCard6024Eは正しく動作していないのでしょうか？
現在のIRQ割込みレベルは７となっています。

すみません。やはりくカード正しく動作していないようです。
http://forums.ni.com/ni/board/message?board.id=1170&message.id=2248
こちらに似た症状の物がありましたが
VISA　ランタイムエンジンという物を入れても解決しませんでした。

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Hi Bentup,
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Best Regards,
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John Passiak

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Attachments:
test_analog.vi ‏162 KB

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Using whatever version of LV the customer requires. (LV5.1-LV2012) (www.carya.nl)

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Hello,
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Hello Chris,
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Regards,
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https://ecatalog.dynapar.com/downloads/E14_DS_702489_2_.pdf
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Hey guys,
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6024E - Error 10846: Unable to retrieve data fast enough error?

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Hi,
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Hi ! HELP NEEDED !!!
i need to sample 12 chanels with 16ksamples/s ....
so its something like ... 200,000 ksamles/s ...
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u can answere also to [email protected]

200KS/s on the 6024E should work fine on 200Mhz StrongARM and 400Mhz XScale CPUs. 200/300Mhz XScales will probably not be fast enough. You will need to download the 7.0f1 patch for LabVIEW and the PDA module to get this level of performance (and to support multichannel).
Due to various factors from both Windows CE and LabVIEW PDA, using the high-level multichannel acquisition VIs in a default PDA install you should expect to be able to acquire somewhere around 10s of contiguous data at 200KS/s. This can be improved to 50s by various means including a lower-level usage of the DAQ driver code. If you require continuous acquisition, this is achievable but more difficult to program, and may not be able to operate stably at 200KS/s.
If you need more information a
bout said lower-level programming please msg me privately.

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Whats the problem?

You would probably get more info on this in the DAQ Discussion Forums, but I can help you out a bit here. The VIs that you are using are very high level VIs so there is a lot going on behind the scenes that you do not see. More importantly, they are synchronous, meaning that you have to wait until they're finished to do anything else. This is probably why your computer is slowing down. The UI may even freeze until you have acquired all the points you requested. I would suggest using the more advanced DAQ VIs to control your system. There are many examples that ship with LabVIEW which demonstrate how to use these. They allow you to build an asynchronous acquisition system so that other tasks may operate while the DAQ board is acquiring data.
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Trouble creating a circular buffer

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Attachments:
sample.vi ‏43 KB

I tried running your VI, but there were many broken lines and missing controls, so it was kind of difficult to see what was happening. One thing I would suggest is using AO Configure to configure the system for Analog Output first. Also, try keeping a count of the number of updates done so that you can compare that with what you should have done. This may give you an idea of what's going on. Let us know what you find out.
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How to decrease counter ?

Hi, and sorry for a newbie question written in bad English...
how can i control the count direction (up/down)of a counter by a DIO?
In my appliance a counter counts the low-high edges of a step frequency signal. (stepper: escap, DAQ: 6024E)
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Dietmar

Dietmar,
Assuming you want to setup the encoder all in HW,
For CTR0, connect UP/DN to DIO6.
For CTR1, connect UP/DN to DIO7.
You can also reference this very detailed application note on using encoders with DAQ STC(the digital chip on our E-Series boards)
http://zone.ni.com/devzone/conceptd.nsf/webmain/6F25CBA2CD73417786256869005E5FC3?opendocument&node=DZ52326_US
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Kevin R

How to wire VI for 2 encoders using NI9401

I have the attached vi that measures period. My understanding is that the NI 9401 can measure period for up to 4 encoders at once. Do I need one DAQ sequence per encoder, (e.g. the attached vi should measure period for 2 encoders simultaneously)? I want to run up to 16 encoders, so, do I need to copy/paste this code 16 times in order to collect period data for 16 encoders simultaneously?
I am using cDAQ9174 and NI 9401. My understanding is that the 9401 can measure up to 4 encoder signals. If I put a second NI 9401 into the cDAQ9174, can I measure 8, or does the cDAQ9174 limit the number of counters that can be accessed independently? If I have to use two cDAQ9174's, plugged into one PC, does Labview recognize the eight slots as unique, e.g. 1-8, instead of two sets of 1-4 for the addressing of the channels?
Any generic advice on measuring many encoders (period) simultaneously is welcome.
Thanks,
Dave
Solved!
Go to Solution.
Attachments:
counter forum feb 13 2013.vi ‏31 KB

-          Even if you put two NI 9401 into the cDAQ-9174, remember that the counters are in the chassis and this device just has four counters.
-          You can run counter tasks in parallel.
-          If you plug two cDAQ-9174, MAX recognizes two different devices.
Regards

Daq 6024e + IR encoder

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