Attaching 2 encoders to a labjack U6
3 replies to this topic
Posted 05 February 2013 - 05:10 AM
Hi, I have been using a U6 for the last 18 months with one rotary encoder attached and would now like to attach a second rotary encoder, but I have been unsuccessful. I cannot obtain a signal from the second encoder. I use daqfactory express software to process the outputs. Is it possible to connect multiple encoders to a U6? Thanks for any help
Posted 05 February 2013 - 09:31 AM
Are you doing quadrature? Quadrature input requires 2 timers, and the U6 has 4 such timers, so yes you can track 2 quadrature encoders.
Posted 08 February 2013 - 03:58 AM
Yes I am using 2 quadrature encoders. I succeeded in connecting both an obtaining signals. The first of which operates fine, works in both directions and is recording the expected number of pulses per revolution, i.e. 400. The second encoder however, after connecting it, it does not work in both directions, in one direction it records 2000 pulses per revolution and 7 in the other direction, even though this encoder should have 500 pulses per revolution. Apologies if this sounds confusing, but do you have any suggestions or ideas as to why this may be please? Thanks for your time
Posted 08 February 2013 - 10:10 AM
That is very strange. Post a link to electrical details for the encoder and describe how you have connected it, and we can take a look. You might need to look at the signals to see what is wrong. You could get a capture with a digital oscilloscope, or actually you could use LJStreamUD to capture the waveforms. Leave the signals connected to the digital inputs (quadrature timer inputs), but the run jumpers from there to analog inputs so you can acquire those analog inputs in LJStreamUD while turning the encoder.
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