Search found 15 matches

by James
Thu Jul 30, 2020 6:53 am
Forum: General Discussion
Topic: Not able to open port in Jetson TX2
Replies: 3
Views: 404

Re: Not able to open port in Jetson TX2

Here's what's wrong: Open() fails to open the port, because it returns 0. If you open "roboclaw.py", and check Open() (lines 1030-1035 in my version), you'll see that Open() is supposed to return 1 on success, and 0 if the serial library raises an exception, which in your case it does. You can try t...
by James
Wed Jul 29, 2020 3:51 pm
Forum: General Discussion
Topic: Need help troubleshooting a burned MCP236.
Replies: 18
Views: 5967

Re: Need help troubleshooting a burned MCP236.

Turns out that controller was not repaired properly... We attempted a live test today. The clamps worked, nothing got fried. But the (repaired) controller failed. I used the Studio app to test the controller, with the motors connected but the wheels of the UGV in the air. Minimal mechanical load. Th...
by James
Tue Jul 14, 2020 1:19 pm
Forum: General Discussion
Topic: Need help troubleshooting a burned MCP236.
Replies: 18
Views: 5967

Re: Need help troubleshooting a burned MCP236.

Nope, I'm referring to an idle state. Measured currents and temperatures are on idle, with motors disconnected and the motor PWM set to 0% via the Studio app. I know of the thermal pads, very convenient, very not messy :) I'll see if I can replace the one on the controller I repaired (though I was c...
by James
Mon Jul 13, 2020 2:38 pm
Forum: General Discussion
Topic: Need help troubleshooting a burned MCP236.
Replies: 18
Views: 5967

Re: Need help troubleshooting a burned MCP236.

I went through the wiring and measured some current values. The measurements are made at the controller BAT+ connection. The older MCP230A runs at ~113 mA idle (no motors connected, motor PWM set at 0). The newer MCP236 runs at ~121 mA idle (identical conditions). Supply voltage is 53.7 V (13-cell L...
by James
Mon Jul 13, 2020 8:21 am
Forum: General Discussion
Topic: Need help troubleshooting a burned MCP236.
Replies: 18
Views: 5967

Re: Need help troubleshooting a burned MCP236.

Update on status after a really long time (coronavirus and some personal issues...) Thank you for all your help. I have managed to repair the controllers, replaced all burned MOSFETs and also one of the gate drivers on the older MCP230A. I also rigged up two really rugged voltage clamp boards based ...
by James
Sun Feb 02, 2020 2:03 pm
Forum: General Discussion
Topic: Need help troubleshooting a burned MCP236.
Replies: 18
Views: 5967

Re: Need help troubleshooting a burned MCP236.

Thank you for offering to Skype. I will make arrangements and PM you (we are UTC+2, so I need to obtain clearance to stay in the lab until late, plus I'll need to find me an assistant if I have to manage probes and scope and the camera in real-time). I will recheck the o-scope settings, since that "...
by James
Fri Jan 31, 2020 7:45 am
Forum: General Discussion
Topic: Need help troubleshooting a burned MCP236.
Replies: 18
Views: 5967

Re: Need help troubleshooting a burned MCP236.

Believe me, everyone here in the company would love nothing more than to send the controller over to you, the most qualified experts to repair it, and save ourselves the hassle. However, as I've mentioned, I live in Greece. I will elaborate on why sending it over is a bad idea... Shipping the contro...
by James
Fri Jan 31, 2020 7:22 am
Forum: General Discussion
Topic: Need help troubleshooting a burned MCP236.
Replies: 18
Views: 5967

Re: Need help troubleshooting a burned MCP236.

Back again, with some results. There was no shortage of pins I think (sry, couldn't resist the pun :D ) My experimental setup is as follows: 13.5V/3A max, regulated power supply. I opted for the low-range of acceptable supply voltage here. A 5.6 Ω resistive load for testing. That is a plain 5W power...
by James
Tue Jan 21, 2020 9:25 am
Forum: General Discussion
Topic: Need help troubleshooting a burned MCP236.
Replies: 18
Views: 5967

Re: Need help troubleshooting a burned MCP236.

Cool. I checked the (omgsotiny!) resistors with the multimeter, without desoldering them. I got a concise 6 Ω measurement across each one, so I guess the resistors are fine. I also checked the pins of the MIC4102s (the gate drivers), but didn't get any short-circuit readings between the pins, not th...
by James
Thu Jan 16, 2020 12:21 pm
Forum: General Discussion
Topic: Need help troubleshooting a burned MCP236.
Replies: 18
Views: 5967

Re: Need help troubleshooting a burned MCP236.

Your BMS is preventing motor regen from going back into the battery which is causing a massive voltage spike in the MCP. Regen causes the voltage on the batteryt rise and the BMS is probably set to disconnect if the voltage rises farther than some point. If the batteries cant take the regen energy ...