Temp monitor

D

dick kennedy

New member
Jun 1, 1998
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Guys,

If I was doing this I would get a thermocouple meter. The wire is cheap and
you can put it everywhere to measure anything from the fridge to the
exhaust manifolds.

There's a Fluke 51 on Ebay coming up soon. I've been drooling over one of
these but already have more projects than I can handle.

Enjoy

Dick Kennedy

>
>-- [ From: Eugene Fisher * EMC.Ver #3.1a PRODIGY ] --
>
>WElllll
>Looks like 10K was a good choice. I just cut off the external probe
>from my $9 Radio Shack unit and measured the probe. It was 9.62K at 80
>degrees F or about 26.6Deg. C. Sorry about the ambient, but this is
>California what can I say. So if it is a thermistor, could be 10K at
>500 ohms per deg. C. I will have to look at the Mosure catalog next
>monday to see if that is likely.
>
>It tests like it is a thermistor not a diode. The Digi Panel uses a pn
>junction of a special transistor so it is quite different and prob. more
>expensive.
>
>-------- REPLY, Original message follows --------
>
>Date: Saturday, 21-Aug-99 05:17 PM
>
>From: John Dolan \ Internet: (jdolan)
>To: John Dolan \ Internet: (jdolan)
>cc: Adohen \ America On-Line: (ADOHEN)
>cc: Emerystora \ America On-Line: (EMERYSTORA)
>cc: Eugene Fisher \ PRODIGY: (JDDP32B)
>cc: John Dolan \ Internet: (jdolan)
>cc: Roger Black \ Internet: (rblack)
>
>Attachment: mimemsg.doc Code: 04P45RI \ Created: Unknown [2 Kb]
>
>Subject: Re: GMC: Temp monitor
>
>For just the thermistor only... Mouser Electronics has a 10K thermistor
> unit for 66 cents.
>
>If we go with the Radio Shack unit, does anyone know what resistance we
>need at 25 degrees C (as there are all kinds of values available, all
>for 66 cents each). I would appreciate a dissertation on the
>considerations on building the probe. Possibly that is that covered in
>the article?
>
>This company, Mouser, is a family company and does not mind small orders
>..
>
>--
>Regards,
>John 74 Glacier
>
>
>
>-------- REPLY, End of original message --------
>
>
>
>Gene 76Palm Beach /Or/CA
>
>GMC Technical Information
>http://www.california.com/~eagle/
>
>
 
Dick

Excuse my lack of knowledge, but what is a Fluke 51?

Wayne Newland

> Guys,
>
> If I was doing this I would get a thermocouple meter. The wire is cheap and
> you can put it everywhere to measure anything from the fridge to the
> exhaust manifolds.
>
> There's a Fluke 51 on Ebay coming up soon. I've been drooling over one of
> these but already have more projects than I can handle.
>
> Enjoy
>
> Dick Kennedy
>

> >
> >-- [ From: Eugene Fisher * EMC.Ver #3.1a PRODIGY ] --
> >
> >WElllll
> >Looks like 10K was a good choice. I just cut off the external probe
> >from my $9 Radio Shack unit and measured the probe. It was 9.62K at 80
> >degrees F or about 26.6Deg. C. Sorry about the ambient, but this is
> >California what can I say. So if it is a thermistor, could be 10K at
> >500 ohms per deg. C. I will have to look at the Mosure catalog next
> >monday to see if that is likely.
> >
> >It tests like it is a thermistor not a diode. The Digi Panel uses a pn
> >junction of a special transistor so it is quite different and prob. more
> >expensive.
> >
> >-------- REPLY, Original message follows --------
> >
> >Date: Saturday, 21-Aug-99 05:17 PM
> >
> >From: John Dolan \ Internet: (jdolan)
> >To: John Dolan \ Internet: (jdolan)
> >cc: Adohen \ America On-Line: (ADOHEN)
> >cc: Emerystora \ America On-Line: (EMERYSTORA)
> >cc: Eugene Fisher \ PRODIGY: (JDDP32B)
> >cc: John Dolan \ Internet: (jdolan)
> >cc: Roger Black \ Internet: (rblack)
> >
> >Attachment: mimemsg.doc Code: 04P45RI \ Created: Unknown [2 Kb]
> >
> >Subject: Re: GMC: Temp monitor
> >
> >For just the thermistor only... Mouser Electronics has a 10K thermistor
> > unit for 66 cents.
> >
> >If we go with the Radio Shack unit, does anyone know what resistance we
> >need at 25 degrees C (as there are all kinds of values available, all
> >for 66 cents each). I would appreciate a dissertation on the
> >considerations on building the probe. Possibly that is that covered in
> >the article?
> >
> >This company, Mouser, is a family company and does not mind small orders
> >..
> >
> >--
> >Regards,
> >John 74 Glacier
> >
> >
> >
> >-------- REPLY, End of original message --------
> >
> >
> >
> >Gene 76Palm Beach /Or/CA
> >
> >GMC Technical Information
> >http://www.california.com/~eagle/
> >
> >
 
Wayne,

The Fluke 51 is a Digital thermometer designed to work with type J or K
thermocouples. This is the modern equivalent of the old thermocouple
bridges that every lab used to have. The wire is cheap enough that you can
place junctions in various places then just plug in whichever one you want
to read.

I've not actually used one myself but the guys in the lab like them. I've
got one of the radio shack units and it tops out at something like 150 F. I
usually keep it handy and use it for everything from checking the temp in
my shop to checking the fridge and ac duct temps. The Fluke is just a
little more flexible.

I just bought a Fluke 87 DVM so that's my mad money for this month.

Dick

>Dick
>
>Excuse my lack of knowledge, but what is a Fluke 51?
>
>Wayne Newland
>

>
>> Guys,
>>
>> If I was doing this I would get a thermocouple meter. The wire is cheap and
>> you can put it everywhere to measure anything from the fridge to the
>> exhaust manifolds.
>>
>> There's a Fluke 51 on Ebay coming up soon. I've been drooling over one of
>> these but already have more projects than I can handle.
>>
>> Enjoy
>>
>> Dick Kennedy
>>

>> >
>> >-- [ From: Eugene Fisher * EMC.Ver #3.1a PRODIGY ] --
>> >
>> >WElllll
>> >Looks like 10K was a good choice. I just cut off the external probe
>> >from my $9 Radio Shack unit and measured the probe. It was 9.62K at 80
>> >degrees F or about 26.6Deg. C. Sorry about the ambient, but this is
>> >California what can I say. So if it is a thermistor, could be 10K at
>> >500 ohms per deg. C. I will have to look at the Mosure catalog next
>> >monday to see if that is likely.
>> >
>> >It tests like it is a thermistor not a diode. The Digi Panel uses a pn
>> >junction of a special transistor so it is quite different and prob. more
>> >expensive.
>> >
>> >-------- REPLY, Original message follows --------
>> >
>> >Date: Saturday, 21-Aug-99 05:17 PM
>> >
>> >From: John Dolan \ Internet: (jdolan)
>> >To: John Dolan \ Internet: (jdolan)
>> >cc: Adohen \ America On-Line: (ADOHEN)
>> >cc: Emerystora \ America On-Line: (EMERYSTORA)
>> >cc: Eugene Fisher \ PRODIGY: (JDDP32B)
>> >cc: John Dolan \ Internet: (jdolan)
>> >cc: Roger Black \ Internet: (rblack)
>> >
>> >Attachment: mimemsg.doc Code: 04P45RI \ Created: Unknown [2 Kb]
>> >
>> >Subject: Re: GMC: Temp monitor
>> >
>> >For just the thermistor only... Mouser Electronics has a 10K thermistor
>> > unit for 66 cents.
>> >
>> >If we go with the Radio Shack unit, does anyone know what resistance we
>> >need at 25 degrees C (as there are all kinds of values available, all
>> >for 66 cents each). I would appreciate a dissertation on the
>> >considerations on building the probe. Possibly that is that covered in
>> >the article?
>> >
>> >This company, Mouser, is a family company and does not mind small orders
>> >..
>> >
>> >--
>> >Regards,
>> >John 74 Glacier
>> >
>> >
>> >
>> >-------- REPLY, End of original message --------
>> >
>> >
>> >
>> >Gene 76Palm Beach /Or/CA
>> >
>> >GMC Technical Information
>> >http://www.california.com/~eagle/
>> >
>> >
>
>
>
>
 
Gene...

>Looks like 10K was a good choice. I just cut off the external probe
>from my $9 Radio Shack unit and measured the probe.

What is the RS model number of your unit? Also you said the wire is
almost indestructable... I have been looking for the wire and can't find
it. Thanks in advance...

- --
Regards,
John 74 Glacier
 
Hi Dick...

>The Fluke 51 is a Digital thermometer designed to work with type J or K
>thermocouples. This is the modern equivalent of the old thermocouple
>bridges that every lab used to have. The wire is cheap enough that you
>can place junctions in various places then just plug in whichever one
>you want to read.

I just noticed that my $129 Radio Shack digital multimeter /w RS232
interface when sold by its real manufacturer Metex, includes a K-type
thermocouple and will read temperatures in two ranges -40 C to 200 C and
200 C to 1200 C. It is the same meter.

Do you or anyone know what and where I need to buy, to get this
capability. Just a thermocouple? Why won't a standard digital meter do
this (too low an input impedance?)

- --
Regards,
John 74 Glacier
 
John

A thermo couple meter measures voltage but there are some special reference
junctions and calibrations involved. The voltages are very low so the
design isn't trivial. That's why most of the cheap thermometers use
thermistors. I've got a cheapie no name meter with a built in plug for a
thermocouple but it's wildly inaccurate.

There's a standard thermocouple plug which is two spades in line. One's
wide and the other narrow for polarization. I think you can buy them and
the wire separate or together. They're also available as a nicely packaged
probe.

Assuming your meter has this special plug you just need to locate the plugs
and wire to be in business. You can even measure your manifolds. Any
industrial supply house should be able to supply it.

There are also adaptors made which just interface a thermocouple to a DVM.
You can probably find more on the web. Really accurate results require a
lot of care.

This is what I would do if I was going to make a lot of measurements but
I've got a fifteen dollar radio shack meter that I actually use for most
everything at home. It gets me by. I just can't measure anything over 150
degrees and there's only one probe. I was driving Sunday and had it in the
AC ducts, out the window and in the cab at various times.

Hope this helps

Dick

>Hi Dick...
>
>>The Fluke 51 is a Digital thermometer designed to work with type J or K
>>thermocouples. This is the modern equivalent of the old thermocouple
>>bridges that every lab used to have. The wire is cheap enough that you
>>can place junctions in various places then just plug in whichever one
>>you want to read.
>
>I just noticed that my $129 Radio Shack digital multimeter /w RS232
>interface when sold by its real manufacturer Metex, includes a K-type
>thermocouple and will read temperatures in two ranges -40 C to 200 C and
>200 C to 1200 C. It is the same meter.
>
>Do you or anyone know what and where I need to buy, to get this
>capability. Just a thermocouple? Why won't a standard digital meter do
>this (too low an input impedance?)
>
>--
>Regards,
>John 74 Glacier
>
>
 
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