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Jrk frequency feedback question


#1

Hello,
These forums as well as some emails have helped me greatly in getting my Jrk G2 24v13 working well on my test bench.

I created a situation by accident that I can not seem to solve browsing the forums.

On my test rig, I have an encoder wheel linked to a motor using a small belt - this is just to test/program the Jrk. Everything works really well - exceeding my expectations however, the motor sheave (pulley) slipped off the motor causing the frequency feedback to drop to 0.
This caused the motor to rapidly spin up to max duty cycle. I found this to be an interesting situation - what if my encoder somehow lost physical contact with my project? I tried to address the potential failure.
I tried to use the Feedback Disconnect error to stop the motor by changing the minimum feedback error value above 0. This did not seem to have any effect - when I remove the belt duing the test, the motor would spin up to max duty cycle.

Is this scenario possible? That is, can I create an error to stop the motor if the physical link from the motor/gearbox is removed and the feedback drops to 0? The encoder is still physically attached to the Jrk so “Detect disconnect with power pin (AUX)” would not help in this situation.

Thanks again for a great little motor controller.


#2

Hello.

I am glad you have had a good experience with the Jrk so far!

The Jrk does not have the feature you are describing, and it would be difficult to make something like that work since the Jrk would need some way of differentiating when the feedback pulses stop because a physical connection failed and when the feedback stops because the motor is stopped.

You might be able to include some kind of additional failsafe by using sensor or switch to monitor the pulley and make sure it is physicaly there.

Brandon


#3

Thank you Brandon,
I figured “Jrk would need some way of differentiating …physical connection failed (or)…because the motor is stopped.” was the case. This little circuit does so much I figured it wouldn’t hurt to ask if it had that trick up its sleeve.
Thanks again for the response! This has been a great learning moment tinkering with the Jrk.