I’m seeing lots of spurious “brown-outs” with the Jrk G2 24v13 controllers. I have a bank of 6. Power is supplied in “star” configuration. They all behave the same way: Random USB disconnection. Upon reconnection “last reset” is “Brown-out reset”. But this doesn’t make much sense as the motor could be doing nothing. Also, completely disconnecting motor power doesn’t trigger a brownout. I’ve tried multiple USB cables, with and without a hub. I’ve tried three different power supplies. I’ve tried “decoupling” my PC’s ground by running my laptop on battery only.
An o-scope on the 3.3v Regulator shows stable voltage through an error.
Max motor current draw is ~>2Amp.
The problem happens lots more when the motor is “Jittering” due to bad tuning. They still brown-out randomly.
If you are seeing brown outs, then that suggests some kind of power issue with your setup. Can you post some pictures and a wiring diagram that show all of your connections along with more details about the power supply and motors you are using? Can you also use your scope to look at VIN and the 5V (out) pin on the Jrks?
Each controller powers a LACT4P-12V-10 linear actuator.
Power supplies tested with include a 25v switching power supply, 24v linear, and a 12v linear. Error exists for all. Things might be stable for a minute of cycling the actuators but a brownout disconnect eventually occurs. Brownout is present regardless of whether the Jrk is wired as a single or in a “star” configuration with the large bank. I’m only testing one Jrk at a time.
This makes it sound like you are disconnecting VIN and GND at the same time (like unplugging a battery) which could damage electronics in your system like the Jrk motor controllers, so please avoid that. In general it is good practice not to disconnect the supply while the motor is driving, and I suggest disconnecting power using an appropriate power switch on VIN or something similar.
Can you post more specific information about the power supply (like a product page or datasheet). Please look at VIN with your scope when the problem occurs as well.
Also, have you tried using the preconfigured Jrk G2 settings file available for your linear actuator on the actuator’s product page under the “Using a Jrk G2 motor controller with a linear actuator with feedback” header?
I did use the preconfigured settings for the linear actuator.
I can’t remember the pn of the power supply at the moment (more later). But it’s a cheap switcher. I’ve also tried two other (under powered) linear power supplies. I’d expect an under-voltage/under-current brownout error rather predictably with those, but no. The brownout disconnect error I’m seeing is spurious, regardless of power supply – mostly unrelated to what the motion is actually happening. But the error does happen during motion. It might be fine cycling for 1 minute. Then the smallest move will cause a disconnect error.
Stay tuned for debugging VIN power for glitches/noise.
Errors appear much less frequently when under analog control. I caught one. The JRK reset and continued under analog control. But USB connection was lost.
I really don’t think my power supply setup is creating these problems. I’ve heavy gage wire for Vin and GND with solid connections to the power supply. I’m only testing one controller and motor at a time in my bank of 6. Vin is distributed to the bank in a “star” configuration.
I’m really hoping you guys can suggest a solution to mitigate these disconnection errors. This is going into some lab equipment that relies on stable and consistent control via USB. I’d like to ship soon.
Can you post scope captures showing what happens when a brown-out reset occurs? Ultimately, if a brown out reset is occurring then it probably will be a result of some connection issue or how your power supply and actuators are interacting. You mentioned observing your power rail surge up to around 40V from back EMF, but it looks like your supply output only goes up to 30V, so that might be causing some unexpected behavior such as triggering some protection circuit to kick in on the power supply.
As far as things you can try, you might see if adding more capacitance near the main VIN and GND pins for each Jrk helps. If you are not doing so already, you might also consider using USB cables that have ferrite beads to limit the impact fluctuations on your main power supply have on your USB power and communication.
Also, it sounds like you are using 24-25V power for actuators that are designed for operation at 12V. Is there a particular reason for that? Do you still see these problems if you lower the supply voltage to 12V?
I can try and capture scope pictures later tonight. But errors are difficult to catch as there are no obvious rising or falling edge to trigger on. The errors are mostly spurious and can occur whether the motor is stationary or moving slow or fast. Errors do happen more during motion.
Again, (I know it’s bad) disconnecting Vin does not trigger a brownout/reset error.
12v motors can run on 24v. (They just go faster and might not last as long ) Duty cycle and watts are bigger factors. Anyway…
Yes, I see the same errors occur when powered at 12v (using either my DrMeter or a Leader LPS151 linear supply).
If I have some caps with high enough voltage rating I’ll try adding some capacitance to Vin close to the supply.
I’m not very encouraged. I’d be surprised if I’m the only one seeing this problem.
It is rare for us to hear about problems like this, and they depend on details of the specific application. Even the wiring of your particular setup may have a role in it. Along with the scope captures, can you also post some pictures so we can look at the wiring for the overall setup (not just the Jrk G2)?
Also, you mentioned testing the system in analog control mode earlier. Do the brown outs still happen if you use analog control mode with the USB cable disconnected?
) Duty cycle and watts are bigger factors. Anyway…