Work then stopped - Communication with laptop :( -FIXED -NOT

Post by **brentp** » Mon Jul 14, 2008 5:15 am

Peter,

Some USB-Serial adapters are poorly shielded or not shielded at all, and are therefore sensitive to EMI radiation emitted from your ignition system. In the past, others have solved this problem by distancing the USB-serial adapter with an additional length of serial cable.

What was the error you saw when it froze- was it the "timeout" message?

How did you get around the problem- did you unplug / replug the USB adapter? Restart the software? Did you have to power cycle the MJLJ unit?

pristic · Post by **pristic** » Mon Jul 14, 2008 5:18 am

Hi Brent,

No errors, it actually froze everything to do with MJ software... completely. Only way was task manager and kill it.
Had to unplug USB, power down the MJ and then connect all back up, restart software, power up MJ and then it was back... changed a few settings, wrote it, commited it, ran the car up to about 5000rpm this time and software had frozen again, guages frozen on 4900rpm etc etc (not consistantly the same rpm, etc)

Pete

Post by **brentp** » Mon Jul 14, 2008 6:48 am

From our experience, those symptoms are indicative of the USB driver/chipset locking up- the software would not normally freeze like that unless the USB-Serial driver crashed deep inside Windows.

Did it absolutely require a power cycle of the MJLJ, or did you do that as well to be comprehensive (so to speak...) In other words, are you able to recover the situation by just dealing with things on the PC side? If you aren't 100% certain, it would be good to re-create the problem and test again.

Also, it would be extremely helpful for you to test on a computer with a standard serial port.

pristic · Post by **pristic** » Wed Jul 16, 2008 3:47 am

Ok, did more testing.
Brent you were right, dont need to power MJ down.
The software freezes, and I get nothing at all. I have to kill the mj process in Task Manager and then restart it (have to see if plugging and unplugging the cable makes any difference)

It still freezes up though, as soon as I start revving... also, not sure if coincedence or not, but I had it running on idle, 1500rpm and got up to 2000rpm turned on the stereo and it froze up.

When you say to distance the USB adapter away, you mean the length of cable or physically move the whole lot away (like into back seat or out of the car? I am assuming the length of cable (so a serial extension cable) but please confirm. (eg, if I use extension cable but have it sitting on front seat with usb and laptop near the MJ unit.

The cable you supplied is quite long, plus the usb adapter I have has a 1m cable... serial on one end and usb on the other. Its all up over 2 meters of cable... you think I still need the extension?

Also, when you say drivers... I am running Prolific driver I got with the cable.
catalogfile=pl2303.cat
DriverVer=07/25/2005,2.0.2.1

Update it from Prolific site you think?

Thanks,
Peter

PS: Good thing is I can make changes now, but need to make change, commit, test, restart softwre, make another change, test, etc - cant get log or realtime changes etc

DannyP · Post by **DannyP** » Wed Jul 16, 2008 10:13 am

Try the laptop out of the car, away from the source of interference, your car! Sometimes it is the wire length and a serial extension helps, sometimes it is RF(radio frequency) interference.

pristic · Post by **pristic** » Wed Jul 16, 2008 11:10 am

ok will do first thing tomorrow morning, kids asleep already and cant start her up and rev

I tried the latest driver from Prolific website, same exact thing.

Will let you know tomorrow how it goes.

Turns out the 'extension' cable I had is not a DB9 serial cable, rather a monitor extension cable so I need to grab one. Will try computer way outta the car first.

If the shielding on the VR sensor and pip/saw wires is not grounded properly make things worse or better or no difference? Reason I ask is that I think the shielding is not grounded on one end, am going to sort that tomorrow too... just to be sure.

Thanks,
Peter

DannyP · Post by **DannyP** » Fri Jul 18, 2008 10:26 am

Don't ground the shielding on both ends, just on the EDIS end, as far as PIP and SAW and VR sensor goes. They should all go to the same point on the frame/chassis, Megajolt included.

pristic · Post by **pristic** » Fri Jul 18, 2008 12:03 pm

Wait, I have shielded wire for the VR sensor and the pip/saw wire. both of these are grounded on one end at the same point... the other ends (ie/ the VR sensor end) is not grounded and the megajolt end (of the pip/saw) is not grounded either. If that makes sense.

So only one end of the shields are grounded at the same point (which also is the same point as the ground for MJ and EDIS)

Should I ground the other ends of the shields?

The newest drivers made diddly squat difference... same crapola.

Thanks,
Peter

DannyP · Post by **DannyP** » Sat Jul 19, 2008 2:09 pm

The grounding you've done sounds fine.

mr_bridger · Post by **mr_bridger** » Sun Jul 20, 2008 10:03 am

i had exacly the same problems you describe with the software freezing whils at the dyno, tried putting laptop ouside of car, but these USB-Serial units have the curcuitry on the MJLJ end so made no difference. in the end had to abort the tuning as every time you spinned the engine up it froze the software...

bought a serial cable and diched the USB one..... havent had a problem since.

if you have to use a USB to Serial, get the circuit end as far away form the car as possible.... not easy though as you need the PC / Laptop close!

i know it sounds mad, and may not work, but how about wrapping some tin foil around the USB/Serial unit? let us know if it works!!

Ross.

pristic · Post by **pristic** » Wed Jul 30, 2008 12:25 am

Tried a laptop with Serial plug - worked perfectly... unfortunately its not my laptop so have to borrow it to muck around but I know it works.