Thermocouple board

A forum for discussing the MegaSquirt related (but non-B&G) board development, assembly, installation, and testing.

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msoultan
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Re: Thermocouple board

Post by msoultan »

excellent. i'm going to continue this discussion on your forum as I need to know what other I/O boards I'll need so I can interface properly with the MS3. I'm excited to get EGT going!

thanks!
Mike
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Re: Thermocouple board

Post by TT350chevelle »

Where is a good place to buy probes? 8 egt probes could be quit expensive.

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msoultan
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Re: Thermocouple board

Post by msoultan »

Yeah, that can be. I was just gonna go through DIY...
jsmcortina
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Re: Thermocouple board

Post by jsmcortina »

Yes, they are expensive, but DIY can price match (when I bought mine anyway) so they are worth using.

I _finally_ installed all of my 8 EGTs last night (outside in the rain) and I'm looking forward to experimenting with them.

James
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racingmini_mtl
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Re: Thermocouple board

Post by racingmini_mtl »

Also, another advantage of the DIY probes is that they have 8-foot leads which is not the case for all probes. This allows you to put the EGT conditioners inside the cabin which is not a bad thing when using screw terminal blocks which are not protected from the elements.

Jean
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Tiberius
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Re: Thermocouple board

Post by Tiberius »

I'm currently trying to build a data logger with arduino. EGT logging is also on my todo list.
Is there any particular reason why you didn't use a multiplexer instead of multiple ad595's? This should drop the price significantly.
I'm also torn between using the ad595 on an analog input and the max6675 on a digital one. The ad is cheaper but the max has integrated cold junction compensation which you'd need to build additionally with the ad.
Does your design incorporate compensation?
Poolside
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Re: Thermocouple board

Post by Poolside »

The AD595 has Cold Junction Compensation.
Last edited by Poolside on Sat Apr 03, 2010 12:04 pm, edited 1 time in total.
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Re: Thermocouple board

Post by racingmini_mtl »

As Jim mentions, the AD595 has cold junction compensation and the AD597 used on my board also has it.

And a multiplexer wasn't used because I did not want to put anything but the strict minimum between the probes and the AD597 to get the best results. I haven't even looked at them to see if there are some that are adequate for the type of signal given by an EGT probe. Moreover, there is no code in MS3 for controlling a multiplexer and the I/O extender has plenty of ADC circuits.

Jean
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Tiberius
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Re: Thermocouple board

Post by Tiberius »

Thanks I meanwhile got both AD datasheets. Seems for my application the use of the max6657 is the way to go because it can talk SPI directly to the arduino and delivers a higher resolution than arduinos own analog inputs. There's literally nothing else required to operate the TC.
h22
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Re: Thermocouple board

Post by h22 »

nice board, I would be interested .
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Re: Thermocouple board

Post by racingmini_mtl »

It has taken me much longer to get around to finish the assembly but here it is:
ImageImage
ImageImage
ImageImage
(click on the picture for a larger view)

You can see the assembled board and the board besides Canadian quarter to show the size (similar in size to a US quarter). Then you have both sides of the board in the acse with the header and then with the screw terminal plugs. The 6-position side is for 12V, ground and the four 0-5V outputs that will go to the ADC inputs. The 8-position side is for the 4 EGT probes.

I will be putting up a web page shortly where it will be possible to order the boards but if you want one you can contact me directly in the mean time. Initially, the board will be available as an assembled board only or as a completely assembled cased unit with connectors. I may have kits available later but I'm a bit reluctant due to the somewhat tricky assembly.

Jean
Last edited by racingmini_mtl on Mon May 24, 2010 11:27 am, edited 1 time in total.
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jsmcortina
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Re: Thermocouple board

Post by jsmcortina »

Those Phoenix contact screw terminal plugs are good. I've used them before.

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
Poolside
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Re: Thermocouple board

Post by Poolside »

Nice. That Hammond case family is new to me. I like it.

Polycase.com has some good ones too, you can never have enough enclosure sources.

Jim
shortbus
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Re: Thermocouple board

Post by shortbus »

So for 8 egt's I would need two of these?
Or will there be a V8 version?

I am interested in either case. PM me/email me with purchase info please.
mr2andy
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Re: Thermocouple board

Post by mr2andy »

Is this board still available? :)
racingmini_mtl wrote:It has taken me much longer to get around to finish the assembly but here it is:
ImageImage
ImageImage
ImageImage
(click on the picture for a larger view)

You can see the assembled board and the board besides Canadian quarter to show the size (similar in size to a US quarter). Then you have both sides of the board in the acse with the header and then with the screw terminal plugs. The 6-position side is for 12V, ground and the four 0-5V outputs that will go to the ADC inputs. The 8-position side is for the 4 EGT probes.

I will be putting up a web page shortly where it will be possible to order the boards but if you want one you can contact me directly in the mean time. Initially, the board will be available as an assembled board only or as a completely assembled cased unit with connectors. I may have kits available later but I'm a bit reluctant due to the somewhat tricky assembly.

Jean
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Re: Thermocouple board

Post by BNZ »

+1 on availability
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racingmini_mtl
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Re: Thermocouple board

Post by racingmini_mtl »

The board is available but only as an assembled board without the case or connectors. There wasn't enough interest to justify having them in stock. So you can have an assembled board but you'll need to buy a case and the connectors from an electronics vendor such as Digikey or Mouser and assemble the complete unit which is somewhat tricky.

Jean
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bcrx7
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Re: Thermocouple board

Post by bcrx7 »

Jean, I don't see the board on your site. How can I order one?
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racingmini_mtl
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Re: Thermocouple board

Post by racingmini_mtl »

bcrx7 wrote:Jean, I don't see the board on your site. How can I order one?
PM sent.

Jean
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frank_ster
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Re: Thermocouple board

Post by frank_ster »

i would like one too. i'm in montreal, i could maybe help with case and connector issues.
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