Volkswagen Mark IV Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
539 Posts
Discussion Starter · #1 ·
Has anyone got a usb-->serial converter working reliably with VAG-COM???

I can't believe the 12MB/s USB link is the bottle-neck. Sounds like the converter

between USB/Serial. I'm guessing different converters may be able to handle

the transfer rates required by VAG-COM.

Any ideas???

Malc
 

·
Registered
Joined
·
1,315 Posts
ill get you the make etc later, i got it off ebay for £12.

mr benn is meeting me tomorrow evening i think, think he has used vag-com b4 so he can possibly confirm its working ok?
 

·
Registered
Joined
·
44 Posts
I haven't used it before but I thought I heard that it didn't work that well through convertors. Maybe Uwe Ross will pick up on this thread.

The company I work for make PC Apps that use COM1 at a highish speed. Some of our recent customers have bought Laptops with no port and they try to use a USB->Com1 and they just don't seem to work very well.

Be interested to see the setup tomorrow Liquorice.

Mr Benn
 

·
Registered
Joined
·
539 Posts
Discussion Starter · #7 ·
What to do is log some info using the measuring block option in the engine section. This will test out the performance of the convertor to the maxmimum. You should get about 3-3.5 samples per second on one measuring block. This will decrease as you log more blocks.

I'm going to try getting the convertors from a couple of high street shops, as I can always take them back if they don't work!!!

Will be interested to know what your one is though!!

Malcolm
 

·
Registered
Joined
·
92 Posts
I think that the reason might have something to do with the voltage levels of the RS232 side of the USB/RS232 adapter not being sufficient.
 

·
Registered
Joined
·
1,315 Posts
Just done this;

Posted Image


this is the usb - serial adapter

Posted Image


No make or model reference on the box.

PS, is my MAF Knackered? no idea what im looking at
 

·
Registered
Joined
·
539 Posts
Discussion Starter · #10 ·

·
Registered
Joined
·
539 Posts
Discussion Starter · #11 ·
BTW, you can alter the delays in VAG-COM to improve the sample rate. I got mine up to 4.5/second.

Posted Image


Try changing Blk Int to 25 and Char Int to 1

This should speed it up. Covered in the FAQ on the VAG-COM website
 

·
Registered
Joined
·
606 Posts
USB<->Serial converters are plenty fast when you're moving big chunks of data, but the old VAG protocol (KW1281) doesn't move big chunks, it moves one byte at a time. The problem with USB<->Serial converters in this application is latency. The "turn-around" time can be as much as 16mS, which is too long for many control modules.

In addition, many USB<->Serial converters do not properly support some of the non-standard baud rates that the control modules want (example 10,400 baud is a MUST for modern cars).

If you find a USBM<->Serial converter that works with everything in your car, fine, use it. Just understand we don't recommend or support them because of the above issues.

-Uwe-
 

·
Registered
Joined
·
539 Posts
Discussion Starter · #13 ·
Well, bought another usb-serial converter at the weekend, which worked straight away and can sample at about 4.5 samples a second on one measuring block. Superb...

Will post a piccy, but again, no manufacturing info on it! Bought from a local computer spares shop.

Malcolm
 

·
Registered
Joined
·
493 Posts
Though I'd drag this thread up again. Has anyone found a USB>>>Serial port adaptor that works? I'm getting fed up of carting the desk top PC outside every time[:D].

Cheers, Jim
 

·
Registered
Joined
·
345 Posts
Yeh im after one as well. Went to PC world and they done sell them. They passed me on to www.partsmaster.co.uk but cant find nothing on their website. Keep meaning to try a local PC shop by me but keeps forgetting.

Malky, if i cant get no joy gettin one, fancy making a few quid and picking me up one. That would be spot on cos at least then i know it will def work.
 

·
Registered
Joined
·
493 Posts
Turbo Batch,

That's the same sort of thing I bought off Ebay. Did'nt work but you never know, that one might.

Cheers, Jim
 

·
Registered
Joined
·
345 Posts
ah feck, dunno wot to do now. Is there any kind of thing im looking for or is it just pot luck???

Edit - found a few on www.maplin.co.uk. Any look familar. i want to connect up my new VAG COM so badly

  • USB to Serial & Parallel - 24.99http://www.maplin.co.uk/media/mediumimages/37209i0.jpg]
  • USB to Serial Adaptor -19.98
    Posted Image

  • USB to Serial 9 Pin Male - 24.98
    Posted Image

 

·
Registered
Joined
·
539 Posts
Discussion Starter · #19 ·
Trial and error i'm afraid!!! Tried 3 before I got one to work. No brand name info on it either so I can't tell you what it is!!!
 
1 - 20 of 20 Posts
Top