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TC4/Artisan Temp Read Issues
James211
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Posted on 02/07/2016 1:11 PM
I may have posted about this before, but cannot seem to remember or find my post, so forgive me if that's the case. I'm having an issue with only one type of probe, the alt BT probe, and I'm not sure why. Eric S. was kind enough to send me a replacement, but I get the same results with the replacement. The reading of the alt BT probe gradually gets further and further apart from the standard BT probe as the temp gets higher. So at 100 degrees, the alt bt and bt read the same. At 200, they start to drift by about 25 degrees, by 300, 75 degrees (Those are rough numbers..). I'm not sure why its doing this, but I'd really like to get the alt bt probe working so I can do smaller batches.

As a comparison, I plugged both probes into my Thermoworks Blutherm duo and the probes read exactly the same. So the problem is either in the artisan software or the TC4 shield. Any other ideas on troubleshooting?

Would anyone have any ideas as to why this is happening?
 
BenKeith
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Posted on 02/07/2016 3:36 PM
I don't know how Artisan works but does it allow multiple PID settings for each probe and if so, are you running the same PID settings on both probes? Different settings on P, I, and D can cause a difference in the set temp and that difference can change with increased temps.

Other than that, the only thing I can think of would be probe placement. Small differences in probe placement can make huge differences in temp readings. Sometimes just moving one a 1/4" higher or lower in the bean mass makes a big difference. Unless they are almost joined at the same spot, it would be hard to say there was anything other than that wrong.
Edited by BenKeith on 02/07/2016 3:48 PM
 
James211
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Posted on 02/07/2016 3:47 PM
I agree with you about probe placement, the issue for me is that there are no beans in there when I'm doing readings, I'm just getting measurements on air temp within the drum itself. When I use a high quality K-Type meter the probes read exactly the same. When I use the TC4 and Artisan for readings, the alt BT is coming in lower as the temp increases.

Maybe I see what the serial monitor straight from arduino reads.
 
BenKeith
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Posted on 02/07/2016 3:54 PM
If you physically change the probes on the input terminals on the TC4, does the one reading higher change also. If you swap the probes inputs on the TC4, if it related to placement, the difference should swap. If it's related to the TC4, changing the inputs would not change the one reading high.
 
James211
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Posted on 02/07/2016 4:02 PM
Regardless of what input the probe is on, the alt BT is always a lot lower.

Serial monitor reads the same as the Artisan software
 
BenKeith
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Posted on 02/07/2016 4:13 PM
Now, you are not going in Artisan and reassigning the probes when you move them are you? Just moving the probes and doing nothing else.

If you are just moving the probes and the BT is always the one that's low, it's back to my first question about the PID settings.
If it's possible to remove the probes, place them side by side and use a heat gun or hair dryer and see what they do. Other than that. not sure.

It they read the same outside the roaster and different inside, then you are back to probe placement.
 
James211
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Posted on 02/07/2016 4:21 PM
I'm not reassigning them. I've tested them in boiling water and steam. Once they start to get close to the 200F marker is when they begin to drift...but again, this in only via the TC4 in both artisan and arduino serial monitor. With a my other K-type monitor they don't change, they stay the same regardless of temperature.
 
BenKeith
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Posted on 02/07/2016 9:32 PM
I have a second TC4 I could try, but that doesn't help you any. I'm out of ideas and don't know of anything else I can tell you to try.
 
James211
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Posted on 02/07/2016 10:33 PM
Any chance I could borrow it if I pay for shipping both ways? I'm also considering trying a slightly older version of the TC4/arduino software.
 
BenKeith
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Posted on 02/08/2016 7:30 AM
I seriously doubt any older version of the older versions will do anything for you. I don't know about Artisan, but the PID program aArtisan and RoastLoggerTC4 use has not been changed in several years.
 
BenKeith
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Posted on 02/08/2016 8:08 AM
Are your running off a separate power supply or the USB port on your computer? MOST USB is just barely enough to run the TC4 and I've seen strange things happen with low voltage. I use a one amp 12VDC power supply that looks like a cell phone charger.

One other suggestion, with the setup you are running, you don't exactly appear to be having to scratch for every dime. For less than $50 you can build you a very basic, spare TC4. I have seen having a spare be very handy several times for me. Matter of fact, pretty soon I will have a third because I just go an email where Jim has just shipped another one I ordered. One of mine quit for strange reason a couple of weeks ago, and I ordered a replacement. Last week it started working again, and has run for several hours since, but I had already ordered a replacement, and I have a couple extra Arduino boards.
One time ordering parts off ebay, I ordered on of those $4 Chinese boards that has the square processor in it, just to see what it was about. Once I found a driver that would work in it, it actually seems to work, but it has to have the driver, Arduino will not recognize it without it. I have never actually put a TC4 on it to see what it does though. Supposedly the more expensive rip off ones that have the same processor as Arduino are fully compatible, but if I was going to pay $12 or more, I would pay the other $12 get the real thing.
 
James211
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Posted on 02/08/2016 8:14 AM
Good point about the power, I'm going to give that a shot. I also have an arduino mega here, I'll give that a shot as well.
 
JackH
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Posted on 02/08/2016 11:27 AM
There is sometimes an issue with metal sheathed probe's cases touching the roaster chassis and causing trouble (Ground loop). I have to isolate my probes from the chassis.

Something to check. Also there are 4 inputs for the TC4 and one may be bad.
---Jack

KKTO Roaster.
 
James211
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Posted on 02/08/2016 1:25 PM
Hey Jack,

How did you isolate the probes? I really think it's only the alt bean probe that has the issue. The others seem to operate normally....or at least I presume they do.
 
JackH
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Posted on 02/08/2016 3:48 PM
I used un-grounded probes. You can also have problems if the probe is close to a source of electrical noise like a fan or motor.
---Jack

KKTO Roaster.
 
ChrisR
Top  #16 Print Post
Posted on 12/27/2017 4:12 PM
I have a somewhat similar issue. I have a couple of dual outputs OMEGA probes. One output from each probe goes to OMRON controllers and one output goes to TC4. When I start the roaster the temperature reading on OMRON and TC4 are within 1F. However, as the temperature rises, the TC4 reading lags behind the OMRON reading by as much as 60F on both probes. The TC4 power supply is connected to the 220v on the roaster to ensure same ground for both OMRON and TC4. The TC4 board is connected to Artisan and graphed via Artisan.
Any suggestions? I currently have TC4 version 6.00, loaded with the latest QPID software, 6.3 and my probes are un-grounded probes. If I remove the power supply and attach the USB cable, the temps are read correctly.
Edited by ChrisR on 01/04/2018 12:03 AM
 
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