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Reading SSI absolute encoder with USB-6008 DAQ

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by "DO", you mean the digital output from the encoder right?  That is, the data you are trying to measure?  You'll want this connected to a line on port 0 so you can take a clocked digital input measurement (not a PFI line).

 

Something like this (you can generate the CSn and CLK with either digital output or with counters).

 

 

Best Regards,

John Passiak
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Message 11 of 49
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Yes, I want to get the data by port "DO" of the SSI absolute encoder, but there is erro when I configure the USB DAQ, can you please explain me the detail connection way? Thanks a lot!

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Message 12 of 49
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That's not very descriptive...

 

Which error?  Did you follow the advice given here?

 

 

Best Regards,

John Passiak
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Message 13 of 49
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Hello John: Sorry for my ambiguously describe. I am not sure I understand your solutions rightly or not. I try to follow the method, but it doesn't work. I use two blocks:  one DAQ to generate the signal for CSn and CLk and other DAQ to input signal for DO, the input DO has some problems. More details I send you the by excl. Would you please help me to solve. Thank you very much!!!

Best regards,

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Message 14 of 49
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The -201062 error that you show in the message you sent me indicates that you can't run a buffered digital input task on the line you have selected.  Buffered lines must be on port 0 (you are trying to run it on port 1).

 

I notice you're using the DAQ Assistant from your screenshot--this won't give you enough control of the device in order to do what you need.  You'll have to use the lower-level DAQmx API.

 

 

Best Regards,

John Passiak
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Message 15 of 49
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Ok, thanks  John. I will try to find the solutions and to see what will be happened.

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Message 16 of 49
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AbsoluteEncoder.png

 

Instructions:

 

Connect p0.0 to CS

Connect p0.1 to CLK AND to PFI0

Connect DO to p0.2

 

 

If you have any further questions please post them here rather than sending a private message.

 

 

*EDIT*  I realized after looking at the timing diagram that this implementation won't be able to pick up the LSB sample, and the first sample it does pick up is not valid.  I'll post another example shortly.

 

 

Best Regards,

John Passiak
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Message 17 of 49
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AbsoluteEncoderCounters.png

 

Instructions:

 

Connect PFI 12 (ctr0 out) to CS

Connect PFI 13 (ctr1 out) to CLK

Connect DO to p0.2

 

 

Best Regards,

John Passiak
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Message 18 of 49
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Hello John: Thank you very much! You are so kind!!!

I will read your method carefully and compile it in my Labview.

If there is any good news and result, I will tell you!

 

Anyway, I will post my question here rather than send you private message.

Thank you once more!

Best regards,

Boborain

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Message 19 of 49
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Hello John: I ever tried to compile the .vi in my Labview 8.6 following your instructions, but always some bugs. So I download the trial version of Labview 12.0 to open the original vi you post for me. But the trial version 12.0 lacks the DAQmx Data Acquisition VIs Functions package. I can't open AbsoluteEncoder .vi and  AbsoluteEncoderCounter .vi, would you please send me the package to see your original .vi? You know this issue puzzled me several days. Thanks a lot!

Best regards,

Boborain

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Message 20 of 49
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