LabVIEW
Read back of Rotary Encoder with 1 volt peak to peak sin/cos signal
Hi Mike,
That definitely sounds like something that NI hardware can handle. All M-Series DAQ cards feature DMA.
There are 2 main considerations here:
A) The maximum frequency you expect from this sinusoidal encoder.
There is no NI hardware that is specifically customized to read sinusoidal encoder signals. Instead, you will need to use an analog input card to sample this encoder signal, and then write software to analyze the waveform and count the number of peaks, and then convert that to a position. To give software enough data to do this analysis, it would good to have a DAQ card that samples at 10 times the highest frequency you expect from this encoder, as this will result in a good signal shape.
B) The rate at which you need to software to provide an update of the position.
Since this position measurement relies on software analysis, the rate at which you can get position updates (and presumably drive a control loop) will also be software dependent. Based on the speed of the DAQmx read function you should expect position updates to take a few miliseconds.
Just for reference, here is a picture that I found on galilmc.com that shows the signals from a sinusoidal encoder. Please verify that this is the type of input you are expecting.
Hopefully this helps you out while you're picking your hardware. If you have any further questions, please let us know.
Have a great day!
Travis W
That definitely sounds like something that NI hardware can handle. All M-Series DAQ cards feature DMA.
There are 2 main considerations here:
A) The maximum frequency you expect from this sinusoidal encoder.
There is no NI hardware that is specifically customized to read sinusoidal encoder signals. Instead, you will need to use an analog input card to sample this encoder signal, and then write software to analyze the waveform and count the number of peaks, and then convert that to a position. To give software enough data to do this analysis, it would good to have a DAQ card that samples at 10 times the highest frequency you expect from this encoder, as this will result in a good signal shape.
B) The rate at which you need to software to provide an update of the position.
Since this position measurement relies on software analysis, the rate at which you can get position updates (and presumably drive a control loop) will also be software dependent. Based on the speed of the DAQmx read function you should expect position updates to take a few miliseconds.
Just for reference, here is a picture that I found on galilmc.com that shows the signals from a sinusoidal encoder. Please verify that this is the type of input you are expecting.
Hopefully this helps you out while you're picking your hardware. If you have any further questions, please let us know.
Have a great day!
Travis W
Message Edited by Travis W on 10-13-2006 05:51 PM
Message Edited by Travis W on 10-13-2006 05:51 PM
