jrk12v12 too often connection lost!

Hi guys, there are problems with jrk? , I still have not been able to test the cards that I come to power supplies 12 volts :? , but when I arrive I will also do tests to see how it works, Greetings! :hi:

Hi christianr3, it seems that the problem is surmountable (I damn hope that..) , today I will be able to do all the tests that I should do today (work and no time today..).
I'm optimistic about the positive solution of this problem after reading this thread but sure I need to do all the test before to start to jump for the joy.
Soon the updates!

:hi: aldos hello, I'm glad to hear that, I also will do tests when I send the power supply, also hope to contribute something to others, in the same way as I also help me : . Luck!

Hello Aldoz, my jrks never failed if thats what you mean. I noticed since I got the big motors that I have the odd motor driver error which is related to overshoot as the motors really can move and take some sorting out. Mostly getting motion profiles right.
I still get the odd error reading comport.... through x-sim 2, but when I click ok, it starts again fine . My current issues seem to be related to the fact that I am pushing the boards VERY hard. Like I run unlimited current, but really I am spiking at between 32-38amps . So the jrks, even with heatsinks and fans get HOT, but never stop. The PID settings I use may not work on your motors , but thats what I use. Contact Eaorobbie to see what he uses on his winch motors.
Always fiddling with profiles, but thats what I get pushing these boards hard.
:

Hello, firstly let me say that thanks to Earobbie, that the JRK boards are the best thing next to sliced bread. They are small, easy to set up, tough, and reliable. Always put a heatsink on the big chip of the board and a fan close to it to cool it.
The issues surrounding them are related to user problems and tuning PID.
I have blown up 5 boards, but from my own mistakes and NEVER related to computer problems. Things like bad USB cables, wrong polarity of 12 volt when the USB cable is attached, lack of earthing of motors, especially wipers. I have probably missed something, but those sort of mistakes are the main destroyers of boards.

The issues like connection lost, error reading comport, motor driver error, max current error and so on are related to the initial set up of the boards through the JRK utility program.
Things like PID, Integral limits, PID period, max duty cycle settings, these can affect the running of the JRK board and cause errors , both through windows, profiler, and the utility program.
Also, depending on the motor and its requirements, this can cause issues as well. Wiper motors are fairly sedate so they cause few issues, mostly max current from too big motion. Larger motors like the winches and big worm gear motors require more attention to get the settings right.
Both Eaorobbie and I have spent a LOT of time changing these settings to suit our motors. I have spend 4 hours straight just getting the PID sorted on mine and I still have made changes. Goodness knows how long Eaorobbie has spent, a lot more time than any of us I'd guess.
Overall, these are a good board, they require some care to set up, mostly getting polarity of voltage right, good usb cables (although I found $3 one from the local pc shop the best), heatsinks on the big chip for cooling with fans, decent quality potentiometers to get good feedback results, either single turn or multiturn. Decent power going in, like a high current power supply and battery in parallel for plenty of power.
So remember, we are hobby builders of motion sims, we should expect to make mistake, but those of us who do can let everyone else know so they can avoid the same problems.
back to racing!
David.

:hi: hi david., you're right, you are very experienced in this topic, as you say Earobbie is a pioneer in the cards :clap: , and it's good to know that help and your knowledge to people that even we are beginning in this world :handshake: . I also hope someday to have some knowledge to help in anything .. but I'm starting and I'll have a lot of mistakes, but so is everything, learn from mistakes, keep in touch! force! ... sorry for my english, but I'm learning :tape:

So remember, we are hobby builders of motion sims, we should expect to make mistake, but those of us who do can let everyone else know so they can avoid the same problems.
back to racing!
David.[/quote]

My pololu PID period is set to 4 ms, which is as low as possible with 128 analog samples, to achieve the quickest response. A very high setting gives lag, which probably doesn't matter in many applications other than motion sim. I tried lowering the datapacket rate from 33 to 16, and then to 4 ms, and then to 1 ms. I just played for 45 minutes with all datapacket rates at 1 ms and there were no errors or connection problems.

I think I will experiment with USO settings and more analog samples later.

Considering the profiler has a standard of 33ms, this may change motion as well, I found with the JRK, depending on the motor used, if the PID rate is too low, it affects the amount of errors in the JRK utility.

Mine never fail or disconnect, I would check your usb, usb drivers for your pc and not the jrk board. Also the power you have going to the board, I use a powered hub to send one line to the pc. i have a seperate pc for the profiler.

Mine never fail or disconnect, I would check your usb, usb drivers for your pc and not the jrk board. Also the power you have going to the board, I use a powered hub to send one line to the pc. i have a seperate pc for the profiler.

didnt read, but need to make sure you have fans and heatsinks

Could everyone PLEASE try to understand this:-
The Pololu JRK was NEVER designed for the abuse we put them through, they handle it though. They were designed to go into battle robots with smaller motors than even wipers. Now the robot guys are using wiper motors after seeing how good they really are.
Some of use including myself use much bigger motors than wipers. Myself use a 180w overdriven 12 volt motor, other use boat winch motors.
We are ALL working through the MINOR issues relating to connection lost.
As said, it seems to be more windows, and jrk setting related than actual mechanical failure of the boards.
Think about it, if you were designed to have a 10 amp motor driven through you, you would complain if the same person put a 16-32amp motor on you. You would have the odd dummy spit as well.
However, the boards still handle it. I have the odd connection lost issue and as I have said , it is related to the fact I am overdriving my motors and pushing the jrk boards very hard. I am working through finding a balance of fierce motion and jrk stability. I can just wind down the motion to stop this quite easily, but it seems I am the pioneer of these motors on this set up, so I am deliberately pushing them too hard to find that balance.
This way, then if anyone else tries the motors, like Christian, they can rest assured that someone else has gone through hours of headache getting the settings right and then SHARING this with others.
The boards are FINE, excellent boards considering what we do with them. Buy them, use them, easy to set up and they can be abused hard.
Cheers, David.

Hi bsft and THANK YOU for your help. Your posts here are always really useful!

Hey dudes, to all, this is the link about connection lost matter in the pololu forum that I opened.
Please take a look, there is a guy really good and ready to help all the jrk lover!


http://forum.pololu.com/viewtopic.php?f ... 724#p24724


PS: dudes, your PID configurations let me to have a really more precise and realistic behaviour about little and big bumpings!! really a big improve than my old poor and weak PID configuration!

These are the relays that were originally installed in the winches for the cable control, yes?
So you're running the motors with full, max power from the battery when the jrk close the relay?

Exactly! with 6 of these relays you can handle 3 motors at full power (a more big power than the unlimited max current and 600/600 cycle and accelleration from the jrk!)
The jrk have to think about just to provide the position order to the motor and to load the feedback position! No longer amps will flow inside the little and precious jrk!!
I think you can continue to edit and use the PID configuration from config utility when you are using the relays method then you can continue to use your parameters to find your personal motor behaviour.

Did you read this bit of the thread?
I don't really understand your relay schematic but I think it will not work. Bidrectional control requires four relays. The jrk outputs a 20 kHz PWM signal that allows it to have fine control, but relays are basically on or off.
Yes a relay would work , but it would only give you a on/off function, full power or full stop, no real control.
Try fiddling with PID first. You are only running you jrks at 25amp from memory, so they are still safe. I run mine at 32-38 amps for spikes in current and they still live - just.

I realize that this is an old thread, but I have been having serious issues with my JRKs disconnecting at random times as well. I went through all manner of things related to windows, drivers, PID settings, duty cycles etc. My motors worked fine using the Pololu setup tool, but failed randomly during races. I haven't had a problem since grounding the cases of my motors. I never had a problem with this until I did a rebuild on my rig. Same motors, same controllers - everything was electrically unchanged, and yet... I had a similar issue a long time ago because I was using 2 separate 12V power supplies. I needed to connect their grounds together or their was excessive noise on the USB lines.

I hope this helps someone!
- Mike