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JRK 21v3 Connection lost

What could cause my JRK 21v3 to say “Connection lost” after running for some time.
Only think I can see, could be some extra amp load.
I have another card with same 24v motor and no issues. I swapped the cards and same issue. Which leads me to believe the issues is with the motor. Same motor but they could have different loads at times.

No errors are shown. I tried limiting the max amp but that doesn’t help. Slower speeds seem to help, doesn’t happen as ofter but still happens

green light is blinking fast, yellow blinks slow. When connection is lost the lights don’t change.

thank you

Hello, twisted8.

It sounds like the load on the motor is causing noise in the system that’s interfering with the USB connection. You might be able to prevent it by using a powered USB hub or a USB cable with ferrite beads at both ends.

Additionally, you could try some of the methods described in this “Dealing with Motor Noise” application note to suppress the motor noise, such as adding capacitors across your motor terminals or adding decoupling capacitors across VIN and GND on the Jrk.


Thank you. I will try this.
I’m also having the strange problem now when the JRK motor moves it makes a servo connected to a maestro card move as well. If I unplug the DC motor then the servo is ok. If I plug it back in and move the DC motor, servo motor moves as well. Is this also caused by noise?
Thank you

Yes, strange (often unpredictable) behavior like servos jittering could be caused by noise. For something like that, you might be able to reduce the jitter by adding some capacitance close to your servo’s power line (i.e. on the Maestro’s servo power rail if you are connecting it directly to the Maestro).

If you are powering your system all from a single power supply, you might consider monitoring the voltage when the motor is moving; the voltage could be dipping when the motor draws significant current, which could cause problems for your system such as brownouts and resets.