Mike W1
05-21-2016, 06:07 PM
Did some strictly NON-scientific testing today. I know K type TC's aren't real accurate and have learned that even the type connectors you put on them can affect their accuracy so decided to do some informal measuring and see what I could learn. Tried to use most of the gear I have that includes 5 TC's, a VOM that will measure temperature, Auber PID unit, 2 Rex PID units, and a dial thermometer.
First measured the melt of a pot that was set at 374°C with as many combo's as I could. Felt like the one legged man in that kicking contest plugging and unplugging TC's. Recorded those figures and then attempted to come up with the errors associated with the various TC's as well as the measuring devices.
For that I used ice water and recorded those differences. Previously I'd done that with the Auber and one TC and inputted the offset (Pb) in there. Reading through the Rex manuals again I finally found out they call their offset parameter SC so that's now part of those units as the TC's are normally dedicated to one rig.
Once I'd done that converted things using the error corrections and came up with the little chart. Learned that the error varies quite a from combo to combo and that the VOM readings are probably a little high if one doesn't figure in the error of the particular TC.
Looks like if one would calibrate their unit and TC it'd be worth doing but still a spread of nearly 10° if your switching gear. But on the other hand that 689° reading on the dial thermometer is pretty much a guess too. It reads closer to the 690 than 680 and that's about it. Good enough. Certainly! But it's very visibly slower responding to temperature changes than a TC is.
Try as I might I cannot figure out how to edit this so the figures stay in the proper column. Unit 2 only has the first two figures so you have to just "slide" things to the right in your mind!
REX C100 REX C100 Auber 2352 VOM
Unit 1 Unit 2
________________________________________
PROBE
1 696 702 697 701
2 693 696 704 697
3 682 694 693
4 697 697 698
5 687 695 690
DIAL THERMOMETER 689°
Control Pot set at 696° F Converted C to F all REX Readings
Readings in "chart" are corrected for temperatures for ice water
Probe #1 Auber WRNK-191
Probe #2 Auber WRNK-191
Probe #3 ebay 4" by 1/8" diameter
Probe #4 ebay 4" by 5mm diameter
Probe #5 ebay 3-1/2" x 1/8" diameter
Both Rex Units offset (SC) then corrected to -005 (9° F) w/ Auber's probes
2352 was offset to -003 initially
TC error varied from 3-9°F and could be corrected in the PID's using the
offset feature. My VOM appeared to agree with the PID's when taking
TC error into account. Maybe 1°F higher!
First measured the melt of a pot that was set at 374°C with as many combo's as I could. Felt like the one legged man in that kicking contest plugging and unplugging TC's. Recorded those figures and then attempted to come up with the errors associated with the various TC's as well as the measuring devices.
For that I used ice water and recorded those differences. Previously I'd done that with the Auber and one TC and inputted the offset (Pb) in there. Reading through the Rex manuals again I finally found out they call their offset parameter SC so that's now part of those units as the TC's are normally dedicated to one rig.
Once I'd done that converted things using the error corrections and came up with the little chart. Learned that the error varies quite a from combo to combo and that the VOM readings are probably a little high if one doesn't figure in the error of the particular TC.
Looks like if one would calibrate their unit and TC it'd be worth doing but still a spread of nearly 10° if your switching gear. But on the other hand that 689° reading on the dial thermometer is pretty much a guess too. It reads closer to the 690 than 680 and that's about it. Good enough. Certainly! But it's very visibly slower responding to temperature changes than a TC is.
Try as I might I cannot figure out how to edit this so the figures stay in the proper column. Unit 2 only has the first two figures so you have to just "slide" things to the right in your mind!
REX C100 REX C100 Auber 2352 VOM
Unit 1 Unit 2
________________________________________
PROBE
1 696 702 697 701
2 693 696 704 697
3 682 694 693
4 697 697 698
5 687 695 690
DIAL THERMOMETER 689°
Control Pot set at 696° F Converted C to F all REX Readings
Readings in "chart" are corrected for temperatures for ice water
Probe #1 Auber WRNK-191
Probe #2 Auber WRNK-191
Probe #3 ebay 4" by 1/8" diameter
Probe #4 ebay 4" by 5mm diameter
Probe #5 ebay 3-1/2" x 1/8" diameter
Both Rex Units offset (SC) then corrected to -005 (9° F) w/ Auber's probes
2352 was offset to -003 initially
TC error varied from 3-9°F and could be corrected in the PID's using the
offset feature. My VOM appeared to agree with the PID's when taking
TC error into account. Maybe 1°F higher!