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Old 01-11-2014, 01:49 AM   #11
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Originally Posted by big_len View Post
If your sensor was wired to pins 7 and 8 then your wiring was indeed correct.

Can I ask where you got your sensor? 2 wire RTD probes (pt100 is a type of RTD) are not all that common, typically 3 wire for hobbyist level gear, and if you bought it from a chinese source on ebay there's a chance it might actually be a type K thermocouple!

When you say no luck with the K setting you had a value from it though? These can be very out at boil, I recently did a calibration on my PID setup in work and it was 8C (14F) out at boiling temperatures...
I was getting a positive reading while only on the 7-8 pin and set as a K. I did buy it exactly how you said, it was cheap (lesson learned). I am considering to just invest on something off auber or an RTD off amazon.

I was reading ~145* at garage temperature
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Old 01-11-2014, 01:52 AM   #12
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Originally Posted by wuttheheeck View Post
I was reading ~145* at garage temperature
Was this in K mode with no jumpers or PT100 mode with jumpers ?
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Old 01-11-2014, 04:03 AM   #13
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Was this in K mode with no jumpers or PT100 mode with jumpers ?
It is in K mode with no jumpers. Getting a closer reading, but still about 15 off. This is consistent with all three therms im using (labled pt-100) but apparently a thermocouple.

Any way to adjust for this difference?

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Old 01-11-2014, 05:01 AM   #14
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Originally Posted by wuttheheeck View Post
I was getting a positive reading while only on the 7-8 pin and set as a K. I did buy it exactly how you said, it was cheap (lesson learned). I am considering to just invest on something off auber or an RTD off amazon.

I was reading ~145* at garage temperature
My pt-100 sensors were $6 and my my pin pies were 21 and 26 bucks and they are both dead on with my infrared temp gun and my two analog thermometers (well within one degree) mine are three wire.
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Old 01-11-2014, 12:22 PM   #15
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My pt-100 sensors were $6 and my my pin pies were 21 and 26 bucks and they are both dead on with my infrared temp gun and my two analog thermometers (well within one degree) mine are three wire.
I would agree with this, I have also done alright with 3-wire low cost probes. I would probably buy one anyway, off ebay, as it only be about $5 as augiedoggy said.

As for this probe, have you tried it in boiling water? It might be a conicidence that its reading close to ambient-ish temperatures in K mode and it is a pt100.
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Old 01-11-2014, 07:54 PM   #16
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Originally Posted by big_len View Post

I would agree with this, I have also done alright with 3-wire low cost probes. I would probably buy one anyway, off ebay, as it only be about $5 as augiedoggy said.

As for this probe, have you tried it in boiling water? It might be a conicidence that its reading close to ambient-ish temperatures in K mode and it is a pt100.
Thank you both for your help, I plan on running a few more tears with the them as they are. If the reading stays x degrees warmer consistently I will adjust my calculations temporarily but then also purchase some better sensors, or at least a 3 wire Pt100

@augiedoggy where did you find them for $6? I could only find bare k type for that cheap, and I've read there are issues extending the leads with xlr cables like my my setup
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Old 01-12-2014, 05:00 PM   #17
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Thank you both for your help, I plan on running a few more tears with the them as they are. If the reading stays x degrees warmer consistently I will adjust my calculations temporarily but then also purchase some better sensors, or at least a 3 wire Pt100

@augiedoggy where did you find them for $6? I could only find bare k type for that cheap, and I've read there are issues extending the leads with xlr cables like my my setup
On eBay... I bought two shipped from supplier in china... they took a couple weeks though... I too have the xlr connectors setup with mine with no issues...
Here's where I bought mine.

http://www.ebay.com/itm/111179002321...84.m1497.l2649
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Old 01-14-2014, 07:04 PM   #18
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Originally Posted by wuttheheeck View Post
It is in K mode with no jumpers. Getting a closer reading, but still about 15 off. This is consistent with all three therms im using (labled pt-100) but apparently a thermocouple.

Any way to adjust for this difference?

If you have a multimeter just measure your probe resistance. If it's PT-100 RTD its resistance should be around 100-120 Omh
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