Is it normal for a Jrk 21v3 to draw almost a quarter amp at 12V with nothing else attached to it? No motor, no USB, no feedback, nothing. When I plug my encoder into the feedback pins (which is spec’d at 5mA max), my current draw jumps to 450mA. There don’t seem to be any specs for nominal current draw for the controller, but this is certainly way higher than I’d have expected.
You must at least have power attached, right? Can you describe exactly how you are powering the jrk and post a picture?
Okay, then, that is definitely not normal. The jrk should only draw about 20mA when it is powered but not doing anything. Did this jrk ever work for you? Is it possible that you created an electrical short (e.g. FB-AUX) when soldering in the header pins?
The thing is, I’m seeing this on multiple boards. I isolated another board and encoder pair in my setup and did the same tests, with similar results. The reason I even noticed in the first place was that I powered up my stack of nine Jrks for the first time, and it was pulling well over 3A. I immediately assumed a short, but after putting the multimeter across the power leads, it doesn’t seem to be the case. Anyway, with the board shown in the pictures, I’m seeing 2 megaohms between FB and AUX, and hundreds of kiloohms between other pairs (FB-5V, FB-Gnd, etc.). In any case, it’s perfectly functional… when everything’s hooked up, I can send commands, the motor spins, it responds to feedback appropriately. It’s just drawing way too much current for my taste. I’m perplexed.
Hmm, that is strange. But did you happen to notice the current draw on any of these boards before wiring them up, configuring them, etc? Can you describe how you constructed this “stack” and post your configuration file? Does the problem get resolved or change in any way if you reset to the default settings?
Also, are you sure that your power supply is giving you the correct reading? Does anything get hot on the jrk?