Probe Calibration


 
J

JHalasz

TVWBB Fan
My probes had to be calibrated -70 degrees, is that normal? I didnt realize how off they were till i checked my meat, i was trying to cook at 225, it was actually 160 or something like that.
 
As long as you have selected the proper probe preset on the configuration panel, they should not need calibrating.

Did you use the correct resistor? You can measure the resistor value and enter that into the configuration page as well, if it isn't correct.

david
 
If you know the probes were ok before plugging them in the HM, and you have the correct resistors installed on the HM for the probes, then try to resolder all the jacks, resistors that are involved with the probes. If that does not work, calibrate the probes in boiling water(San Antonio) which is 210.9-211. Don't let the probes touch the bottom and keep them moving in the water. Also you can use ice water. fill the glass with ice and add water, insert the probes and stir keeping the probes moving, while testing. If they are way off, more then 5-10+ then maybe its time to get new probes. ET Maverick probes are known for failing, although I have had some last for years.
 
John Bostwick said:
If you know the probes were ok before plugging them in the HM, and you have the correct resistors installed on the HM for the probes, then try to resolder all the jacks, resistors that are involved with the probes. If that does not work, calibrate the probes in boiling water(San Antonio) which is 210.9-211. Don't let the probes touch the bottom and keep them moving in the water. Also you can use ice water. fill the glass with ice and add water, insert the probes and stir keeping the probes moving, while testing. If they are way off, more then 5-10+ then maybe its time to get new probes. ET Maverick probes are known for failing, although I have had some last for years.
Click to expand...

As soon as my meat is finished i'll try the boiling water, these probes are brand new out of the package. I noticed my temp wasnt what it should be, so i grabbed my old maverick redi check and it's probes and verified. I also checked the thermo on the front of my egg and it was also telling me my new probes were off... weird, just weird.
 
hmm, what probes do you have again, earlier you said ET7/72 and ET-73

The different probes from Maverick are ET7(not sure if these are different probes then the others), ET72/73, ET73, ET732, ET733.

On the HM the presets are for the ET72/73(Are mostly sold out on the net) and ET-732 probes.

So if you bought ET73 probes they may need to be calibrated on the HM to get the coefficients
 
Last edited:
in my house at 74 degrees, they are reading way high, i put them in boiling water and 1 of them was reading 240+ the other was slightly over 212...
 
That is very unusual. I am actually considering removing the offset configuration item because the offset at most should be 1 or 2 degrees. anything else indicates something is definitely wrong either in hardware or the wrong probe coefficients are being used. It might be the probes are not the curves we are expecting, or possibly a bad connection?

Excuse the brief reply, I am out of the country until this evening so I am typing on my phone.
 
I am almost certain that the ET-72/73 probes are the same as ET-72 and ET-73 probes (internally) so they should follow the same curves. If you plug each of them into your original Maverick Redi Check and then swap the probes around in the plugs (does that model have two simultaneous inputs?) the values should stay the same right? If they both work just fine in either jack of the Maverick unit, there's no reason they should read differently on the HeaterMeter.

You can also measure their resistance while unplugged and they should read the same (I think it's around 200kohm at room temperature / 77F?). Now plug them into HeaterMeter's FOOD1 and FOOD2 ports (not PIT) and change the setpoint to "0R" (zero R, case-sensitive) on the configuration page then switch back to the home page. FOOD1 and FOOD2 should be reading the same resistance value you saw on the multimeter. If they don't match what the multimeter said, then you've got a HeaterMeter board problem or connection issue. If they match what the multimeter said, maybe the probes are actually different and it warrants further investigation.
 
I bought the following two probes (one for pit and one for food) and see a slight difference in readings:

This one reads 183.7kohm with a meter and 186kohm in HM (at room temp of ~78)
http://www.amazon.com/exec/obidos/ASIN/B008OWZMMW/tvwb-20

This one reads 189.7kohm with a meter and 194kohm in HM (at room temp of ~78)
http://www.amazon.com/exec/obidos/ASIN/B004W8B3PC/tvwb-20

I tried probes on FOOD1, FOOD2 and FOOD3 and got same resistance readings. I do think the two probes are slightly different since the resistance delta is consistent across all three ports.

Or maybe I have a board problem since they don't match my meter exactly? or maybe my digital multimeter is to blame?

EDIT: The 2 probes here are the last 2 listed on the HeaterMeter 4.2 Hardware page in the "Power, Probes and Blower" table.
 
Last edited:
Is there a question in there? :-D

If you're trying to get HeaterMeter to exactly match your multimeter, then just adjust the 10000 resistance for all your probes in the webui configuration until the output resistance matches. The problem would be that as the thermistor resistance changes, the ratio between the reference and the probe changes, which will skew your results at other temperatures.

It would probably be better to unplug the probes and measure the resistance of your 10k resistors in circuit then use that value. That's going to be as close as you're going to get to accurate as far as HeaterMeter goes.
 
Well, I guess my question is do I have a problem that I should chase? :) The probe readings are within 1-2 degrees of each other at room temperature in the FOOD jacks. That seems reasonable to me but your earlier post (#13 in this thread) made me think I should at least ask.
 
Haha oh! I wouldn't worry about it. Apparently Maverick thinks they're both "close enough" so I'm not sure if it is worth the effort. If they're off by like 20 degrees, then something is seriously wrong but outside of measuring the 10k resistors like I mentioned, there's not much else you can do to calibrate a thermistor probe.

A thermocouple can be sort of calibrated because it has a linear response where the thermistors are logarithmic.
 
You must log in or register to reply here.

 

Back
Top