Maverick Probes


 

Kevin Scott

New member
I purchased a set of the Maverick ET-732 Food and Pit probes and just hooked them up. My LinkMeter is sitting on my Kitchen table and has a ET-72 probe in the ambient jack. The Ambient probe is reading a steady 78.3 degrees. The pit probe (ET-732 - Probe 0) is cycling through different values starting at 76.3 then it jumps to 76.7 for a couple of seconds, then it jumps to 77.2, then 77.7 then 78.1 then 78.5 then 79.0. It then reverses, moving down through the same temps in sequence until its gets to 76.3 and the the it starts all over again...

I am seeing the same behavior on the ET-732 food probe in the probe 1 jack. It is also cycling through basically the same values (slight difference).

The probe cables are extended (mostly) and you can only see this on the web interface. The LCD reads steady values for each of the probes.

Does this seem right?

7908353374
 
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That is not what I see with mine. Granted I have the "pit" probe, so I don't know if that is different that the "food" probes, but they have the same thermocouple.

Mine move up and down by 1/10 of a degree.

One thing to check is that they are not pushed too far into the jack. If they get pushed too far they won't work. This can make them act flaky. I ended up putting a collar on mine so I wouldn't push them in too far.

dave
 
sounds like serial connection maybe getting some garbage. If the temps are showing stable on the LCD and are changing constantly on the web interface. check all your connrction between the heatermeter and the router.
 
So the probes are plugged in correctly, if I move the ET-72 probe into the pit jack (and change its configuration) it now reads steadily. And if I move the ET-732 into the ambient jack, I see the same behavior as I saw when it was in the "Pit" jack. If I push the probes to far into the jack, it doesn't read at all...
 
sounds like serial connection maybe getting some garbage. If the temps are showing stable on the LCD and are changing constantly on the web interface. check all your connrction between the heatermeter and the router.

Actually I was mistaken, the LCD is reading the same values, its just whole numbers so it didn't appear to me at first to be changing as much. So I believe the serial connection is fine.
 
Kevin,

Take a look at this thread: http://tvwbb.com/showthread.php?23677-Pit-probe-OK-but-food-probes-show-OFF

In there Bryan says how to set the LM to report the raw resistance values. You can see if looking at those makes a difference. If you see the resistance changing in a similar fashion as the temp, then the LM is working fine.

I pulled up the NADC Code table (basically the numbers that convert the resistance to temp) and at 74 degrees it is 4057 and 79 is 4052 at 12bit (I think we are effectivly 12bit, Bryan can confirm). Not too much resolution at that temp. It is well before the knee of the curve. Once the temp gets over 100F it should track better. The ET-73 probes have their knee much earlier so they have better accuracy at a lower temperature.

You could try putting both in a pot of water and heating the water and seeing how they track.

dave
 
Thanks Dave, I will give both suggestions a shot and report back.

Kevin,

Take a look at this thread: http://tvwbb.com/showthread.php?23677-Pit-probe-OK-but-food-probes-show-OFF

In there Bryan says how to set the LM to report the raw resistance values. You can see if looking at those makes a difference.

I pulled up the NADC Code table (basically the numbers that convert the resistance to temp) and at 74 degrees it is 4057 and 79 is 4052. Not too much resolution there. It is well before the knee of the curve. Once the temp gets over 100F it should track better. The ET-73 probes have their knee much earlier so they have better accuracy at a lower temperature.

You could try putting both in a pot of water and heating the water and seeing how they track.

dave
 
Here are the two graphs. Y-axis is NADC value (directly correlates to resistanc) X-axis temperature.
ET-732
ET732NADCGraph.jpg

ET-73
ET73NADCGrapth.jpg
 
Here is a link to a 15 movie showing the values as they change (raw resistance)...

Kevin,
what does it look like when you put it in boiling water?

At 220F it should be rock solid, if it isn't then there is definitely something wrong. I'll get mine out tomorrow and take a look at my resistance changes at room temp.

dave
 
Kevin,
what does it look like when you put it in boiling water?

At 220F it should be rock solid, if it isn't then there is definitely something wrong. I'll get mine out tomorrow and take a look at my resistance changes at room temp.

dave

..
I think you mean 212 at sea level and about 202 at denver
 
So I live in El Paso Texas, my house is at about 3600 ft altitude. So when I put the probe in boiling water it gets up to about 209-210 degrees. But it still bounces around between 207 - 210 in a fashion similar to what you see at room temperature. Once again, with the ET-72 probe its pretty stable moving only a few tenths. But with the ET-732 it bounces about 3 degrees... I'm pretty sure that its the probes, Can I put a meter on the probes and check the resistance to see if that is bouncing about as well?

Kevin,
what does it look like when you put it in boiling water?

At 220F it should be rock solid, if it isn't then there is definitely something wrong. I'll get mine out tomorrow and take a look at my resistance changes at room temp.

dave
 
So I live in El Paso Texas, my house is at about 3600 ft altitude. So when I put the probe in boiling water it gets up to about 209-210 degrees. But it still bounces around between 207 - 210 in a fashion similar to what you see at room temperature. Once again, with the ET-72 probe its pretty stable moving only a few tenths. But with the ET-732 it bounces about 3 degrees... I'm pretty sure that its the probes, Can I put a meter on the probes and check the resistance to see if that is bouncing about as well?

When you configured LM to show the resistance that is what you should you were doing, looking at the resistance. Yes you can try it out with your meter. To use the meter, just set it to the proper resistance range and touch the probes to the two places on the jack. Do it not do it when plugged into the HM as you won't see the right thing.

Just to remind me, if you plug the ET-73 probe into the same jack it works just fine?

dave
 
It does, Obviously I have to change the probe type in the linkmeter\heatmeter configuration, but the ET-72 probe seems to be working fine. Its only the ET-732 probes that are displaying this behavior. I purchased 6 of the ET-732 probes, 2 Pit and 4 food. It appears that I can duplicate this with each of the probes. The temp bounces around as shown in the movie. Even the resistance values you posted are not close. On my linkmeter ) in the move, I'm seeing "900000+" values and in your chart they should range from 250 - 4200. is there some type of conversion that should be done to get corrected values?

When you configured LM to show the resistance that is what you should you were doing, looking at the resistance. Yes you can try it out with your meter. To use the meter, just set it to the proper resistance range and touch the probes to the two places on the jack. Do it not do it when plugged into the HM as you won't see the right thing.

Just to remind me, if you plug the ET-73 probe into the same jack it works just fine?

dave
 
I have used both ET-72 probes and the ET-732 probes without problems. But, I have heard that the ET-732 probes have alot more problems then the older probes. I visisted a friend recently and he had a ET-732 and he said he had to get new probes because the one that came with it did not work.
 
It does, Obviously I have to change the probe type in the linkmeter\heatmeter configuration, but the ET-72 probe seems to be working fine. Its only the ET-732 probes that are displaying this behavior. I purchased 6 of the ET-732 probes, 2 Pit and 4 food. It appears that I can duplicate this with each of the probes. The temp bounces around as shown in the movie. Even the resistance values you posted are not close. On my linkmeter ) in the move, I'm seeing "900000+" values and in your chart they should range from 250 - 4200. is there some type of conversion that should be done to get corrected values?

The values in the table I posted are not resistance. They are the values the ADC converter come up with. The probes are 1Mohm thermocouples so at 77F it should read 1e6 ohms. It looked like from the values in the movie that it was pretty close to this. Here is the table of resistance to F:
F R
-76 2.24E+08
-58 1.01E+08
-40 4.80E+07
-22 2.39E+07
-4 1.24E+07
14 6.68E+06
32 3.73E+06
50 2.16E+06
68 1.28E+06
77 1.00E+06
86 7.86E+05
104 4.93E+05
122 3.17E+05
140 2.09E+05
158 1.40E+05
176 9.59E+04
194 6.68E+04
212 4.74E+04
230 3.41E+04
248 2.50E+04
257 2.14E+04
266 1.85E+04
284 1.39E+04
302 1.06E+04
320 8.11E+03
356 4.95E+03
392 3.14E+03
428 2.06E+03
464 1.40E+03
500 9.71E+02
538 6.92E+02
572 5.05E+02
 
I use both as well. I use the ET-732 as the pit probe and the ET-72 for the food. The only reason I use the ET-732 for the pit is that it has a wider temperature range and that fits my pit temps better. I use the ET-72 probes for the food, because its temperature range is better suited for the food.

I also tweaked my hardware to better center the ET-732, but it was just my OCD that caused that :)

dave

I have used both ET-72 probes and the ET-732 probes without problems. But, I have heard that the ET-732 probes have alot more problems then the older probes. I visisted a friend recently and he had a ET-732 and he said he had to get new probes because the one that came with it did not work.
 
Kevin,

I just got my LM out and plugged it in. When I doe the sp=R, I get 785244.3 (86F) for my ET-732 probe and it sits there solid. No moving until I touch the probe. I do see a slight fluctuation in readings of my ET-72 probe, but not much.

It seems unlikely that all probes would be broken, but I do know that the ET-732 is much more "delicate" than the ET-72. Can you exchange them maybe?

dave
 
Thanks for all the information Dave, it really helps. I went ahead and fired up the Bullet and decided to do a test run using the new pit probe. I don't have any meat in the cooker but once the temps got up to operating range, things are setting down. Here is a 30 min video showing what I see now on the web page. I still don't have the food probes in yet but for me, the pit is more important then anything... I can allways revert back to the ET-72's for the meat since they have been working fine...

I would love to know what is causing the temp flux in the ET-732's though...


Kevin,

I just got my LM out and plugged it in. When I doe the sp=R, I get 785244.3 (86F) for my ET-732 probe and it sits there solid. No moving until I touch the probe. I do see a slight fluctuation in readings of my ET-72 probe, but not much.

It seems unlikely that all probes would be broken, but I do know that the ET-732 is much more "delicate" than the ET-72. Can you exchange them maybe?

dave
 

 

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