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Why have Pulse disturb when we use DAQ Card6024 in PDA to collect waveform
richarden
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05-10-2005 02:46 AM
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NI Tech-Support Department:
I am your client who bought DAQ Card 6024E , we use them to develop instrument for collecting vibration waveform . we have developed driver for WINCE 3.0 (PDA ), it run very well ,but sometimes it display error waveform which is very strange , after 80 ms there is a pulse to 8.99V ,9.99V and then the value is 2.499V and –2.499V,-4.99V etc . and the value would keep for 40ms or 90ms.
But we test the card on notebook–Computer, the condition would not be found .
We want to know what cause the condition , Is it hardware error or software error ? Do you have some examples wrote in C language . Please mail the examples to market@CaiHongFei.com if you have .
Please help me ! Thank you very much!
Shenzhen CHF Hi-tech Co,Ltd
86-755-26547365, 13602549257
I am your client who bought DAQ Card 6024E , we use them to develop instrument for collecting vibration waveform . we have developed driver for WINCE 3.0 (PDA ), it run very well ,but sometimes it display error waveform which is very strange , after 80 ms there is a pulse to 8.99V ,9.99V and then the value is 2.499V and –2.499V,-4.99V etc . and the value would keep for 40ms or 90ms.
But we test the card on notebook–Computer, the condition would not be found .
We want to know what cause the condition , Is it hardware error or software error ? Do you have some examples wrote in C language . Please mail the examples to market@CaiHongFei.com if you have .
Please help me ! Thank you very much!
Shenzhen CHF Hi-tech Co,Ltd
86-755-26547365, 13602549257
Otis
NI Employee (retired)
05-11-2005 11:22 AM - edited 05-11-2005 11:22 AM
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It sounds like what you are running into is problems related to higher continuous acquisition rates. This would explain why what you are doing appears to work on the Laptop, but not on the PDA.
What are the rates that you are trying to run the DAQCard at in the PDA? If you are trying to run the acquisition continuously, then you will not be able to run at rates above about 4kS/s. However, if you are just trying to acquire N Samples, then you should be able to acquire at or near the max rate specified by the board.
The reason for the difference in speed for continuous acquisition is due to the PCMCIA protocol being interrupt driven and due to slower processor speeds in the PDA.
A possible solution that would allow you to continuously sample at higher rates in a PDA would be to use a Compact Flash Acquisition device such as the NI CF-6004 CompactFlash Data Acquisition for PDAs. This device will allow you to sample at much faster rates than a PCMCIA device.
All of the examples that we have for the PDA are written in LabVIEW. However, if you wanted to make C calls to the DAQmx Base driver and then had a C-code compiler for your PDA device, then it would be completely possible to have a DAQ program written in C.
What are the rates that you are trying to run the DAQCard at in the PDA? If you are trying to run the acquisition continuously, then you will not be able to run at rates above about 4kS/s. However, if you are just trying to acquire N Samples, then you should be able to acquire at or near the max rate specified by the board.
The reason for the difference in speed for continuous acquisition is due to the PCMCIA protocol being interrupt driven and due to slower processor speeds in the PDA.
A possible solution that would allow you to continuously sample at higher rates in a PDA would be to use a Compact Flash Acquisition device such as the NI CF-6004 CompactFlash Data Acquisition for PDAs. This device will allow you to sample at much faster rates than a PCMCIA device.
All of the examples that we have for the PDA are written in LabVIEW. However, if you wanted to make C calls to the DAQmx Base driver and then had a C-code compiler for your PDA device, then it would be completely possible to have a DAQ program written in C.
Message Edited by Otis on 05-11-2005 11:22 AM
