looking for a meter to go with E61 thermocouple adaptor

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dsc

#1: Post by dsc »

Hi everyone

I'm planning to buy Eric's TC adapter and wanted to couple it with a TC and a panel meter. The machine I want to install it in is an Andreja Premium and I plan to cut out a hole in the front case to put the meter inside. I wanted to keep the cost down, but unfortunately it's quite hard to do, well at least it's harder than I thought.

The first thing is the TC which costs around 30$. I need to plug it somewhere, so I thought of buying a panel meter, thinking that it would be cheaper than a regulator. Alas it's not, so I'm pretty much looking for a panel meter/regulator with a TC input. The main problem with cheaper PIDs/meters is their accuracy and resolution. I would love to have something with 0.1*C resolution and 0.2-0.3% error, but such equip. costs a fortune. The cheaper ones only offer 0.1*C resolution for RTD's like Pt100 or Cu50 which will be too slow to use on the group (although most offer 0.2-0.3% errors). On the other hand I'm not so sure if I need that 0.1*C resolution, as errors might be as high as 1*C.

So the main question is, what would you suggest for under 80-100$ (around 50GBP as I live in the UK) ?

Would love to here your ideas and thoughts:)

Cheers,
dsc.

User avatar
starry

#2: Post by starry »

I believe that the inexpensive PID from Auberins will resolve to your requirement if you use a platinum thermocouple. They sell one for $10 and the PID is about $35.
Ralph Walter

User avatar
jesawdy

#3: Post by jesawdy »

I'd suggest sourcing the TC from Eric if he has what you need and the Auber Instruments unit is a good suggestion. The 1/32 DIN PID is $35 and can display 0.1C or 0.1F. You could also source a used PID from eBay and just use it as a temperature display unit.
Jeff Sawdy

User avatar
dsc

#4: Post by dsc »

Hi

well just to make things clear:

- Pt100 and Cu50 are RTD's (resistance temperature detectors) which are very accurate but slower than TCs

- TCs (thermocouples) are very fast but need additional compensation and cheaper PIDs don't offer 0.1*C resolution (I think because of the noise which would make the resolution useless anyway)

- thermistors, which are kind of similar to RTD's but are based on semi conductivity, quite fast, quite accurate and might be the thing to use

I'm still not sure which one I want. I was pretty confident to go with a TC, but now I'm not so happy about spending 150$ for a meter which will give me the option to have 0.1*C resolution.

Cheers,
dsc.

PS. that Auber PID offers 0.1*C only when using a Pt100. For TCs it's still 1*C only. Actually I've emailed them asking a question about resolution and they suggested using a thermistor. Anyone here who knows a lot about temperature sensors?

BradS

#5: Post by BradS »

Here's another decent reference for comparing sensors:
http://www.controleng.com/article/CA6434738.html

User avatar
cannonfodder
Team HB

#6: Post by cannonfodder »

I use a Fluke 54 II. I know you are looking for a panel mount option, but after a few weeks of use you will not need the adapter any longer. Nice thing about the Fluke, I can use a Scace and the group adapter at the same time.
Dave Stephens

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erics
Supporter ◈

#7: Post by erics »

The most expensive part of either the thermocouple adaptor kit OR the digital thermometer adaptor kit is the adaptor (and its associated parts). One aspect of the adaptor is to "get you inside your machine" in a fairly easy manner.

A solution for you would be to use the digital thermometer adaptor and purchase the thermocouple adaptor kit ($4) for possible use later on. Now true, you would be limited to a 1/8" probe (whether it be a thermocouple, an RTD, or a thermistor) but you can have a lot of worthwhile fun with the thermometer and take your time in researching the various other temperature measuring options available (should you determine that they would be better suited FOR YOU). Not only that but you can also ponder the surgery :( you describe on Andreja's casework which, IMO, you MIGHT regret later on.

More info available here: http://users.rcn.com/erics/
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

User avatar
dsc

#8: Post by dsc »

Hi all

It looks like I'm going to buy a new PID regulator which normally costs around 150$, but I might pay only 40$:) Will see how the auction goes.

Now the next problem is fitting the damn thermocouple in the group. Normally I would buy Eric's adapter, but because I'm on a tight budget I would love to cut costs a bit. I found similar TC adapters on Swagelok (Erics original idea) and Omega (OMEGAlok fittings) which both cost around 10GBP (but shipping for Swagelok costs a whooping 8 GBP, the same as the fitting alone:|). Now as Eric already noticed (and most of you on HB) there's a problem with screwing the fitting in the group as the hole is in a hollow. I came up with and idea to custom make a thread converter which would look like this:

Image

The only problem is I can't find anyone who would make one for me. I was hoping to get it done in Poland (I'm originally from Poland) but most lathe operators won't do small quantities (I only need one or two).

I can always buy a second group screw, drill it and use some epoxy to stick the TC in place. I wouldn't want to do it as it means the screw is stuck to the TC for good and because the TC costs 15GBP it would be cool to use it in the future without something stuck to it.

I know that someone on HB did drill a M6 screw and it worked. Was it you cannonfodder?

Cheers,
dsc.

User avatar
HB
Admin

#9: Post by HB »

dsc wrote:I know that someone on HB did drill a M6 screw and it worked. Was it you cannonfodder?
See Naked Truth of E61 Temperature Revealed.
Dan Kehn

User avatar
cannonfodder
Team HB

#10: Post by cannonfodder »

dsc wrote:
I know that someone on HB did drill a M6 screw and it worked. Was it you cannonfodder?

Cheers,
dsc.
Yes, it was me. I would not do it again though, pain to do.
Dave Stephens