I installed Phidget RTD's to monitor ET and BT about a year ago in my roaster and use Artisan software. Today while I was roasting, all was going well when my BT reading became erratic and started reading negative. After that roast finished (flying by the seat of my pants), I checked for updates on both Artisan and Phidget control panel and installed updates on both. I rebooted my computer and restarted Artisan and it seemed to have fixed the issue until about 9 minutes into the second roast and the same thing happened again. I've check all connections and all look good.
BTW, the ET probe is reading as it should.

Any thought on what my be the cause of this?

Anything else you changed recently on your measuring setup or your machine?
Are you running the latest firmware on the TMP1200 and HUB? You can check this by opening the Phidgets Control Panel (keep Artisan closed). Modules with new firmware are marked red. A click will update the firmware.

Other potential problems that can be the reason:
- electrical interferences eg. from switching a strong motor or a magnetic valve
- the wires connecting the probe to the module got loose
- your BT probe might be broken. The internal insolation around the sensor element can get broken (eg. by the bouncing beans) allowing a contact with the shield which closes a ground loop

No, nothing has changed on my machine since my last roast which worked fine. After this occurred, I checked Artisan to see if it had the latest update and it hadn't so I updated software. I also checked Phidgets and did the same. I'll go back in Phidgets control panel to see if there are any other updates but the ET probe is working fine. I then checked all wire connections and unplugged and remated all connectors to ensure good contact. At this point, I'm leaning toward a probe issue. I went into drum and cleaned probe and found that my Phidgets BT probe was in contact with the original BT thermocouple probe which leads me to believe something shifted around in drum. After reading through your suggestions, I'm now thinking I may have a broken probe.

So I did check the Phidgets control panel and there were firmware updates available for the modules so I installed them. I then fired up the roaster and brought it up to operating temp and all is well. Thanks so much for the help! I'll make a note to self to check this in the future and keep it updated.

Wowsers....thanks for the heads up on that...I just checked 'out of curiosity' and my phodget drivers were outdated by approx 2 years..so much for the 'convenience' of being nagged about the available software updates from other programs that I got lulled to sleep about this one!

Follow-up on this thread... after several more roasts, problem started again. Seems to be stable until I charge roaster with beans and the BT probe drops out every time. I've checked all connections and they are good. After roaster cooled down tonight. I wiggled sensor with the Phidgets control panel open and was able to get intermittent readings with fluctuations. I think I have a bad sensor. Only a year old, maybe I'll order two so I'll have a spare. Bummer! Also checked firmware and needed another update so I'd advise to check software for updates often.

Seeking advice concerning installation of new Phidgets RTD BT probe in light of previous info in this thread. The failed probe was installed fully inserted into drum. Since these probes are pretty thin and subject to quite a bit of vibration and turbulence from turning beans, should I install the new probe with less of the probe surface inserted into drum? Just trying to get more life out of the probe since the last one was only a year into service at maybe 4 roasts per week. I had made some mild hand-forming to probe to make a very slight bend in probe to clear vanes in drum.

I had similar problems. I noticed if I disconnected my ET that the problem went away. So I thought bad RTD and ordered another. Same issue. Problem just popped up randomly but it would mess up roasts

I never resolved it. I just removed the ET probe and moved on. No issues over 1.5 yrs, LOL

Alaroast wrote:Seeking advice concerning installation of new Phidgets RTD BT probe in light of previous info in this thread. The failed probe was installed fully inserted into drum. Since these probes are pretty thin and subject to quite a bit of vibration and turbulence from turning beans, should I install the new probe with less of the probe surface inserted into drum? Just trying to het more life out of the probe since the last one was only a year into service at maybe 4 roasts per week. I had made some mild hand-forming to probe to make a very slight bend in probe to clear vanes in drum.

Gremlins.

If possible, test the probe on a separate device, Hub link, outside roaster. I think intermittent shorts can be hard to suss out. Phidgets probably have all grounding issues tidied up, but with my TC4 setup with thermocouple probes, I have to have the Huky very well grounded or there is noise and sometimes intermittent signal loss. Recently I thought I would need to open my electronics box and sort all the connections, but before I did, I disconnected and reconnected in a difference configuration, then it all worked. SO I returned it to the roaster and resumed my roasting the next day with no problems since. None of this is mains voltage so it's safe to live with a short, but frustrating.

Does anyone use anything on the thread to isolate the RTD from the roaster body?