com port or USB

Gorman · 11-29-2006, 12:31 PM

Hi Guys; for data logging purposes...will the com port be quick enough or is USB a must. Does it depend on the laptop ? I read the com port type are unreliable...is that true ? Just looking to start monitoring the ecu with with an old laptop under then seat. cheers BigG

bensenvill · 11-29-2006, 12:42 PM

speaking only from a computer aspect, serial ports are much more reliable than USB [in fact if it offers you the choice, the USB is almost certainly using serial port emulation anyways].

a serial port is relatively slow for transfering data and I'm not sure how much data is really transfered with the data loggers but I can only guess that it is well within the abilities of a serial port.

Gorman · 11-29-2006, 12:55 PM

Cheers for that T. "a serial port is relatively slow for transfering data and I'm not sure how much data is really transfered with the data loggers but I can only guess that it is well within the abilities of a serial port." Anyone have any idea of data rates and how big files can get over say a week ? Thanks G.

DemonSVT · 11-29-2006, 06:17 PM

Well answered already.

A serial port is very limited in the amount of total polls per second it can log. (i.e. transfer rate) Expect to be able to log 5-6 categories at multiple polls a second. Anything slower then this is not worth datalogging. This port is very reliable and consistent.

A USB interface does not have this limitation but is also less reliable/consistent.

I've had no problems datalogging with Alex Pepper's OBD-II setup and it uses a serial port connection.

bensenvill · 11-29-2006, 06:47 PM

Quote:

Originally Posted by DemonSVT

Well answered already.

ya, I was all excited, its probably going to be the only question in the tuning section I will ever be able to answer.

Gorman · 11-29-2006, 07:24 PM

Thanks DSVT; for the clarification; 5 or 6 parameters will probably do, to start with. I can't imagine the data; over a week, would overflow the 20G hard drive....unless someone knows otherwise. cheers G.

bensenvill · 11-29-2006, 07:27 PM

no it wont get anywhere close to that.... and if it does, you'll have more data then you'll ever be able to analyze

Gorman · 11-29-2006, 07:39 PM

Hi T. i was hoping to check out the A/F ratio and see if I'm running rich/lean thru the rev. range...the motor rev's OK, but it seems to lack real urgency. First step then..get connected... cheers G.

bensenvill · 11-29-2006, 08:03 PM

no, keep us posted, I'm going to be picking up some datalogging equipment in the next few weeks so it will be nice to know answers to these questions also [that and the laptop I'd be using only has a 850meg hd]

cpapashley · 11-30-2006, 04:52 AM

Oh how I wish it was that simple for me.....

But please post some details. I think it will be full of surprises

Will be looking on with interest.

11-29-2006, 12:31 PM	#1 (permalink)
Gorman NECO Member Join Date: Mar 2006 Posts: 789 Images: 5	com port or USB Hi Guys; for data logging purposes...will the com port be quick enough or is USB a must. Does it depend on the laptop ? I read the com port type are unreliable...is that true ? Just looking to start monitoring the ecu with with an old laptop under then seat. cheers BigG __________________ 2.5L MTX. SVT ECU. Cold air feeds. 65mm P+P TB. Port matched SVT upper to SVT LIM. MSDS Headers. Optimized Y pipe. Test pipe. Wish list. 4X4 wtb xcal

11-29-2006, 12:42 PM	#2 (permalink)
bensenvill is moving his car Join Date: Aug 2003 Location: Chicago Posts: 13,236 Blog Entries: 4	Re: com port or USB speaking only from a computer aspect, serial ports are much more reliable than USB [in fact if it offers you the choice, the USB is almost certainly using serial port emulation anyways]. a serial port is relatively slow for transfering data and I'm not sure how much data is really transfered with the data loggers but I can only guess that it is well within the abilities of a serial port. __________________ 1994 Lincoln Towncar w/ 112576 1996 Contour SE MTX loaded w/ 137179 1999 Silver Frost ATX original owner w/ 70500 RUNNING!!!!

11-29-2006, 12:55 PM	#3 (permalink)
Gorman NECO Member Join Date: Mar 2006 Posts: 789 Images: 5	Re: com port or USB Cheers for that T. "a serial port is relatively slow for transfering data and I'm not sure how much data is really transfered with the data loggers but I can only guess that it is well within the abilities of a serial port." Anyone have any idea of data rates and how big files can get over say a week ? Thanks G. __________________ 2.5L MTX. SVT ECU. Cold air feeds. 65mm P+P TB. Port matched SVT upper to SVT LIM. MSDS Headers. Optimized Y pipe. Test pipe. Wish list. 4X4 wtb xcal

11-29-2006, 06:17 PM	#4 (permalink)
DemonSVT NECO Member Join Date: Oct 2001 Posts: 2,112	Re: com port or USB Well answered already. A serial port is very limited in the amount of total polls per second it can log. (i.e. transfer rate) Expect to be able to log 5-6 categories at multiple polls a second. Anything slower then this is not worth datalogging. This port is very reliable and consistent. A USB interface does not have this limitation but is also less reliable/consistent. I've had no problems datalogging with Alex Pepper's OBD-II setup and it uses a serial port connection. __________________ My 2000 SVT Contour 13.47 @ 102mph - All Motor

11-29-2006, 07:24 PM	#6 (permalink)
Gorman NECO Member Join Date: Mar 2006 Posts: 789 Images: 5	Re: com port or USB Thanks DSVT; for the clarification; 5 or 6 parameters will probably do, to start with. I can't imagine the data; over a week, would overflow the 20G hard drive....unless someone knows otherwise. cheers G. __________________ 2.5L MTX. SVT ECU. Cold air feeds. 65mm P+P TB. Port matched SVT upper to SVT LIM. MSDS Headers. Optimized Y pipe. Test pipe. Wish list. 4X4 wtb xcal

11-29-2006, 07:27 PM	#7 (permalink)
bensenvill is moving his car Join Date: Aug 2003 Location: Chicago Posts: 13,236 Blog Entries: 4	Re: com port or USB no it wont get anywhere close to that.... and if it does, you'll have more data then you'll ever be able to analyze __________________ 1994 Lincoln Towncar w/ 112576 1996 Contour SE MTX loaded w/ 137179 1999 Silver Frost ATX original owner w/ 70500 RUNNING!!!!

11-29-2006, 07:39 PM	#8 (permalink)
Gorman NECO Member Join Date: Mar 2006 Posts: 789 Images: 5	Re: com port or USB Hi T. i was hoping to check out the A/F ratio and see if I'm running rich/lean thru the rev. range...the motor rev's OK, but it seems to lack real urgency. First step then..get connected... cheers G. __________________ 2.5L MTX. SVT ECU. Cold air feeds. 65mm P+P TB. Port matched SVT upper to SVT LIM. MSDS Headers. Optimized Y pipe. Test pipe. Wish list. 4X4 wtb xcal

11-29-2006, 08:03 PM	#9 (permalink)
bensenvill is moving his car Join Date: Aug 2003 Location: Chicago Posts: 13,236 Blog Entries: 4	Re: com port or USB no, keep us posted, I'm going to be picking up some datalogging equipment in the next few weeks so it will be nice to know answers to these questions also [that and the laptop I'd be using only has a 850meg hd] __________________ 1994 Lincoln Towncar w/ 112576 1996 Contour SE MTX loaded w/ 137179 1999 Silver Frost ATX original owner w/ 70500 RUNNING!!!!

11-30-2006, 04:52 AM	#10 (permalink)
cpapashley NECO Member Join Date: Sep 2006 Location: Cleveland Australia Posts: 685	Re: com port or USB Oh how I wish it was that simple for me..... But please post some details. I think it will be full of surprises Will be looking on with interest. __________________ A Mazda MPV is really only a cougar in family friendly clothing............

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