Jrk G2 Open Loop Analog Input Not Full Scale

I’m bringing up a Jrk G2 21v3, using open loop (no feedback) control via an analog input (10k potentiometer connected to the SCL/SDA/GND pins as shown in the user manual). I’ve tried using the scaling input setup wizard as well as manually adjusting the values, and both seem to make sense, based on the values of the analog input I’m seeing. As a note, I’m going for unidirectional control, which comes up in the warning on the wizard, which is fine.

However, the actual duty cycle being outputted doesn’t seem to be “fully scaled”. By that I mean the duty cycle is zero when the pot is zero (good), and it increases as the pot is turned (good), but it hits 100% duty at only about 30% of the max analog input.

The attached image shows this behavior. The graph is me turning the pot. You can see they correspond fairly well until I hit about 30% of the max input, at which point the rest of the input is disregarded (presumably being treated as above the input max).

ANy input on what might be going on would be appreciated!


The Jrk G2 controllers function slightly differently in open-loop mode. A target of 2048 still corresponds to the motor being off, but a target of 2648 corresponds to 100% duty cycle instead of 4095. You can read more about this in the Setting up open-loop control section of the Jrk G2 user’s guide. So, if you change the maximum target value in your scaling settings to 2648, you should get the behavior you want.

If that does not fix the problem, could you post a copy of your Jrk G2 settings file as well as an updated description of what happens? You can save a copy of your settings file from the “File” drop-down menu of the Jrk G2 Configuration Utility while the controller is connected.


Thank you! I can’t check it until tomorrow, but I have to believe this is the issue. I swear I read that section, but somehow missed that!

Thanks again.

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