USB disconnects with pololu jrk 12v12

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USB disconnects with pololu jrk 12v12

Postby thaparser » Mon 8. Sep 2014, 13:41

hi gents,
I keep getting alot of disconnects while running my 2DOF racing sim.
at times it works for an entire race, but most of the times it disconnects or crashes the Converter several times during a race. of course, this makes it unusable.

I'm running Windows 7 64bit system and tested with another PC and a laptop via network and the behavior is the same. I use an USB hub between the JRKs and the PC (tried several hubs already, all powered hubs).
now, there are a few possibilities: either my jrks are the problem or the problem is the USB interface.
I've tried the high-speed plugin and settings, tried several things regarding thread priority and response time with no luck.

the next thing I would want to try is to command the JRKs via serial connection (leaving the USB out). I've also ordered a Kangaroo x2 and Sabretooth 2x25 to try to replace the JRKs as I'm out of options.
anybody tried using the UART/Serial connection? anybody experienced similar problems with USB-to-serial command and control while using the x-sim?

thanks in advance for any feedback you might have!
cheers
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Re: USB disconnects with pololu jrk 12v12

Postby RacingMat » Tue 9. Sep 2014, 09:31

Hi!

Maybe you can investigate the wiring:
- Maybe you have short-cuts with ground?
- did you use shielded wires?

Can you share with us some pictures?
Mat
2 DOF playseat : arduino, motomonster, 12V truck wiper motors
http://www.x-sim.de/forum/viewtopic.php?f=37&t=943
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Re: USB disconnects with pololu jrk 12v12

Postby thaparser » Tue 9. Sep 2014, 09:39

RacingMat wrote:Hi!

Maybe you can investigate the wiring:
- Maybe you have short-cuts with ground?
- did you use shielded wires?

Can you share with us some pictures?
Mat


Thanks Mat!
- I use the Smolka motors and those aren't linked to the ground as you *
- I use shielded wires for pot control and regular USB cables for communication with PC (the powered hub uses 3.5Amps so there shouldn't be an issue). Should I use shielded wires for motor power as well? I use a 30Amp power source for each motor.

I'll take some pictures in a few hours but what exactly should I focus on for these pics?

Thanks again!
cheers
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Re: USB disconnects with pololu jrk 12v12

Postby RacingMat » Tue 9. Sep 2014, 10:00

>what exactly should I focus on for these pics?

I don't know: wiring, PSU... we have to find what happend.

Maybe your PSU is too weak?
2 DOF playseat : arduino, motomonster, 12V truck wiper motors
http://www.x-sim.de/forum/viewtopic.php?f=37&t=943
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Re: USB disconnects with pololu jrk 12v12

Postby thaparser » Tue 9. Sep 2014, 10:17

RacingMat wrote:>what exactly should I focus on for these pics?

I don't know: wiring, PSU... we have to find what happend.

Maybe your PSU is too weak?


Okay, I'll try to be as thorough as possible. It may be that the PSU is too weak but since I'm using 1 PSU for each motor I was hoping this wouldn't be an issue. I've checked the errors on the JRK config software and there were none related to current.

I've been searching on the Pololu forum and found these pointers for motor noise so I'll give those approaches a try to see if I can get the right behavior.

thanks!
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Re: USB disconnects with pololu jrk 12v12

Postby thaparser » Tue 9. Sep 2014, 11:02

meanwhile, I found something that point out the fact that the JRK's USB module is very sensitive and much as we try isolating it from noise, it is prone to this behavior.
Ultimately: "We kept having trouble with the native USB connection. For the benifit of future users it is far easier to use the serial connection. With a TTL serial cable (you can buy nice cables which have the USB to Serial built in the USB plug) it works perfectly all the time. So if you are struggling with the same problem you might want to consider just leaving it and switching. There are no real disadvantages of using serial coms."

Now, the tricky question is: how can we configure x-sim to operate the JRKs in serial mode? (by using the TTL RX signals and an USB-to-Serial adapter away from the motors and all, carying only the GND+RX lines from the PC/USB adapter to the JRK)

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Re: USB disconnects with pololu jrk 12v12

Postby RacingMat » Tue 9. Sep 2014, 12:43

good find! :o

about JRK serial mode, it's beyond my knowledge
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http://www.x-sim.de/forum/viewtopic.php?f=37&t=943
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Re: USB disconnects with pololu jrk 12v12

Postby thaparser » Tue 9. Sep 2014, 14:42

I'll first try re-wiring my sim to see if there's any improvement. I'll also add the capacitors as recommended to reduce noise as much as possible, then if all this fails I'll have to switch to serial connection control.

I'll probably try the Kangaroo+Sabertooth first since it has native support with x-sim (via remote USB-to-TTL using FTDI driver or directly using serial connection control). Again, I'll need to find out the proper set-up for x-sim but it seems that the protocol is simple enough, we'll see.

I'll keep you posted as I advance with this.

wish me luck! :-D=
thanks and cheers
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Re: USB disconnects with pololu jrk 12v12

Postby thaparser » Tue 9. Sep 2014, 19:17

1. no luck with soldering capacitors across motor terminals and twisting motor leads.
1.a X-sim converter crashes, JRK config tool said it lost connection - I can select the JRK again from the list and if I restart the X-sim converter it is able to resume functionality.
1.b X-sim converter reports that an interface was unplugged and asks me to choose an axis. I can select the JRK from the list in its config tool but the converter won't identify it unless I unplug it and plug it back again. It also happened that after I restarted the converter it was still not recognized and I had to unplug it and plug it back. at this point, the JRK has the green led blinking slowly (it is waiting for the OS to reinit the USB bus communication with it).

2. no luck after adding capacitors to the GND+VIN on the JRK. behavior is similar to 1.a and 1.b

more to come..
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Re: USB disconnects with pololu jrk 12v12

Postby tronicgr » Tue 9. Sep 2014, 22:28

Perhaps you can use these big capacitor type battery along your normal PSU for the motors.
http://www.newegg.com/Product/Product.a ... 49X1M61362
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