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Old March 17th, 2019, 04:39 PM   #6
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Join Date: Jun 2012
Location: Australia
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tarik's last link has the details on how I did it - let me know if you need more info.

One thing I will add - as the technote says, the speed parameter is a 32-bit parameter, which chews up two of your precious four datalinks. However it need not be this way under all circumstances. In my application, the encoder was turning quite slowly, and I was able to be quite confident that unless someone decided to run the motor up to several thousand hertz, my value was never going to get so large that it couldn't be represented using only the first 15 bits. So there was no point me wasting a datalink on a parameter that was going to be zero 100% of the time, and I only used the one datalink. Depending on your application, you may be able to do the same. I *think* there may also be a parameter you can play with that effectively adjusts the resolution of your speed feedback, meaning if you did have a higher speed but didn't need the resolution/accuracy, you could get the speed in say 10's of RPMs instead of 0.01's of RPMs, and then scale it in the PLC - the would also help get you in under the 15-bit limit.

Hopefully there's enough data there to get things moving - if not let me know and I'll try to dig out my old files.
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