Emerald with RS232 USB converter

Emerald with RS232 USB converter

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Discussion

steve-V8s

Original Poster:

2,910 posts

255 months

Tuesday 28th April 2009
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Are any of you Emerald K3 people successfully using an RS232 to USB converter ? My unit works well in all respects when connected to a PC with onboard 232 port. When using a PC which only has USB ports via a converter it runs fine until the engine is running. It will run all day in live settings or data logging but as soon as the engine is started the communication drops out. I have tried two different converters with one being slightly more tolerant than the other. Looking at the RS232 signal with an oscilloscope it is obvious that there are quite large short duration spikes which seem to disable the converter. Communication can only be restored by unplugging and then re plugging the converter and restarting the software. Attempts at filtering the spikes without degrading the RS232 have so far not worked. The ECU has a good clean supply and ground It would be interesting to know how others are getting on.

GreenV8S

30,479 posts

291 months

Tuesday 28th April 2009
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Are you getting noise on the 12V supply or ground lines?

steve-V8s

Original Poster:

2,910 posts

255 months

Wednesday 29th April 2009
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GreenV8S said:
Are you getting noise on the 12V supply or ground lines?
No, if I look directly across the supply pins it looks fairly clean. I can see some noise most of which I take to be from the alternator, the large spikes are not apparent, well not as voltage spikes anyway. This was my initial thought as the ECU is switching relatively high coil and injector current to ground via one fairly small pin and the car has very small battery fitted. Before taking the scope to it I put a 1000mF and a 0.1 across the pins internally. I currently have about 18 inches of 24/02 directly to the battery terminal. I was thinking last night that perhaps I should try doubling that up after reading that the coil current was clamped to 9A.

The problem is, I suspect, with the USB device which seems very intolerant of any noise, instead of generating an error and carrying on it simply falls over which often seems to be the case with “new improved” systems. RS232 is so simple and robust.

fatjon

2,298 posts

220 months

Wednesday 29th April 2009
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Have tried several USB to serials with my emerald and one or two other ECUs non were reliable. With the Emerald on the Cerbera I can't even reliably download the map with the engine not running. It almost invariably crashes the connection between half way and 80%. With the engine running and bit of alternator noise etc it is useless. I just got hold of a donkeys years old laptop with a real serial port and a £30 inverter to run it of the fag lighter.

Jon

rev-erend

21,536 posts

291 months

Wednesday 29th April 2009
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Steve - give TVRLeigh a shout .. he is a whiz at this problem.. knows his stuff.


steve-V8s

Original Poster:

2,910 posts

255 months

Wednesday 29th April 2009
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In a way pleased to hear that others have the problem as well as that sort of eliminates a specific problem with the computer. Bit surprised that you can’t get it to work with the engine not running. Both of the converters I have tried work fine for reading and loading the maps, logging and live settings with the engine off.

I guess the thing to do now it to work out if it is the Emerald software not talking to the USB driver well or if it is actually the driver that is falling over. The comms is at fairly high speed and so far have not managed to read the data directly outside the Emerald software. If I can get a terminal emulator or a bit of VB code to read the data and then start the engine that may suggest what is happening. I am told that the actual packet size and frequency is the same it is just the content that changes with the engine running. I am a bit suspicious about this as one of the converters works for about 20 seconds after starting and then drops out which sort of suggests a buffer is filling up or something like that. What I am saying I suppose is I am not entirely convinced it is the noise that is casing the problem.

paulathome

686 posts

225 months

Saturday 2nd May 2009
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Steve,
Have you tried turning down the FIFO buffers. Go to
Control Panel.
System.
Hardware
Device Manager
Ports.
Comm Port 1 (or what ever comm port number you are using)
Port settings.
Advanced.
Then move sliders to the left on FIFO TX and RX buffers.
This should increase the reliablity of the connection.
Might be worth a shot.
Cheers.
Paul.

Edited by paulathome on Saturday 2nd May 13:09

steve-V8s

Original Poster:

2,910 posts

255 months

Saturday 2nd May 2009
quotequote all
paulathome said:
Steve,
Have you tried turning down the FIFO buffers. Go to
Control Panel.
System.
Hardware
Device Manager
Ports.
Comm Port 1 (or what ever comm port number you are using)
Port settings.
Advanced.
Then move sliders to the left on FIFO TX and RX buffers.
This should increase the reliablity of the connection.
Might be worth a shot.
Cheers.
Paul.
Hi Paul. Yes tried setting the buffering as low as it would go, which seems to vary depending on the driver. On the more reliable one the lowest setting is 64 (bytes presumably) the other driver just has a high low medium slider.




dnb

3,330 posts

249 months

Wednesday 6th May 2009
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Make sure your USB to serial converter uses an FTDI chipset. These are considerably more reliable than the ones containing the Prolific chipset.

eliot

11,727 posts

261 months

Thursday 7th May 2009
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Or try a PCMCIA RS232 card (ebay) - you get a "proper" COM1 with a UART.

steve-V8s

Original Poster:

2,910 posts

255 months

Thursday 7th May 2009
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eliot said:
Or try a PCMCIA RS232 card (ebay) - you get a "proper" COM1 with a UART.
Now there is a good idea, will look at that.

eliot

11,727 posts

261 months

Thursday 7th May 2009
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I bought a dual serial port pcmcia adapter from this seller:
http://shop.ebay.co.uk/merchant/pridopia_W0QQ_nkwZ...
Works with my BMW diags and quite handy for work because I can access two Cisco routers at the same time. What I like about it is that it always comes up as com1/com2 - no messing around like the USB ones which seem to select random COM port numbers.

They are a little bulky mind you.

Edited by eliot on Thursday 7th May 12:12

steve-V8s

Original Poster:

2,910 posts

255 months

Thursday 7th May 2009
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Sadly small the laptop I got specifically for this task doesn’t have a slot. Have reached the conclusion that it is the converters that are crashing and not the Emerald code. There is a fair bit of noise on the signal coming from the ECU but to be fair it works fine with a proper port. It seems t only solution is to build an RS232 - USB converter that actually works.

eliot

11,727 posts

261 months

Friday 8th May 2009
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Or purchase an old ibm t22 or dell latitiude 600 laptop. Most tuning /diag software works on old kit just fine.
Also dont forget the possibility of getting a docking station or port replicator as they tend to have rs232 ports also.

paulathome

686 posts

225 months

Saturday 9th May 2009
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It might be worth trying several different types if you can.
We have a lot of trouble at work with our own test software being installed on new machines which sadly don't have a proper RS232 port. Some converters work perfectly while others either crash on a regular basis or just don't work at all.
Also have you tried getting hold of some inch diameter ferrite rings and threading the RS232 cable through it 2 or 3 times to see if it will kill any of the spikes which seem to be causing the trouble.
Paul

spitfire4v8

4,017 posts

188 months

Saturday 9th May 2009
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Steve are you actually using the emerald recommended rs232-usb converter or one youve sourced yourself?
I've used the emerald supplied converter on 3 different laptops and mapped probably hundreds of emerald ECUs without any communications problems whatsoever.

steve-V8s

Original Poster:

2,910 posts

255 months

Monday 11th May 2009
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Yep
First of all I got one from the local “computer shop” and found that crashed so got one of the ones recommended on the Emerald web site which works slighty longer before it falls over. Not been able to play with it for a week or so because of other commitments but hope to sort it out at the weekend.

Mark Adams

356 posts

267 months

Monday 11th May 2009
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I can't stand USB-RS232 converters. Got a box full of them that I've tried over the years. You find you have to have a particular one with each application, and they're al a bit flaky.

Since I discovered the joys of the PCMCIA-RS232 adaptor I've never had any problems, with different software or laptops. These do not work for DOS applications however.

leorest

2,346 posts

246 months

Monday 11th May 2009
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Blackbox and Brainbox are good makes but all USB-RS232 converters seem to be flaky to some extent.

steve-V8s

Original Poster:

2,910 posts

255 months

Sunday 5th July 2009
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I have cracked this one now. Tried all sorts of things but the simple solution was to wind an unscreened section of RS232 cable through a nice chunky ferrite core a few times. The comms are fine now.

I could see spikes on the signal (presumably ignition interference) but when connected to a proper 232 port they were quenched, not so on the usb converter units which seem to be a higher input impedance and fall over at the slightest bit of noise. The ferrite core soaks up all the noise.