"EN1" only ticks at high speeds. Tick count wrong

Questions about using encoders with the Roboclaw product line
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yongwony
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Joined: Wed May 19, 2021 6:48 pm

"EN1" only ticks at high speeds. Tick count wrong

Post by yongwony » Wed May 19, 2021 7:43 pm

Hello,

I am using a V5 2x7A RoboClaw connected to my Windows 10 computer running Basicmicro Motion Studio.

I have a 12V battery connected to the RoboClaw with the LB-MB jumper in place.

A small 10,200 RPM motor with quadrature encoder is connected to the M1A and M1B outputs, 5V output from the RoboClaw for the encoder and EN1 input. The output from the encoder is 5V TTL at 48 counts per revolution (counting both edges of both channels). The motor is free spinning with no load.

So the problem is this: 1 encoder input (EN1) on this particular RoboClaw is behaving very weirdly. Below ~38% duty cycle, it doesn't count at all even though the motor is spinning at a good rate. Even when it's above 38% duty cycle and counting, it counts slower than it should. At 100% duty cycle I get a velocity of ~5600 on the EN1 input. That's far below the theoretical max velocity of 8160 and the actual velocity of ~8600 that I get on EN2 on the same RoboClaw with a fully charged battery. I get the correct ~8600 velocities on every other encoder input on the 4 RoboClaws that I have. (2 of 2x7A and 2 of 2x15A)

I am running the latest firmware on all my RoboClaws

I bought this RoboClaw more than a year ago, and I do not know if EN1 input on it ever worked because this is the first time I am using encoders with RoboClaws.

I am reluctantly concluding that there is a hardware problem with EN1 on this particular RoboClaw but just inspecting the board visually, I am not seeing any damaged components or anything different about the EN1 header pins. Would you agree with my assessment that this is a hardware problem? And if so, is there a component you think is borked and I can replace?

Thank you for your help,
Yongjae

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Basicmicro Support
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Joined: Thu Feb 26, 2015 9:45 pm

Re: "EN1" only ticks at high speeds. Tick count wrong

Post by Basicmicro Support » Wed Jun 02, 2021 11:47 am

Please take pictures of the encoder signal lines on an oscilloscope and email support@basicmicro.com about this. If the encoder signals are clean and noise free then it could be a problem with the encoders(excedingly rare). Noise is the usual cause of problem. This is especially common on motors with hall effect encoders built in(eg cheap china motors).

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