Troubleshooting Electrical Noise with Roaster Thermometer [Solved] - Page 7

Discuss roast levels and profiles for espresso, equipment for roasting coffee.
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drgary
Team HB

#61: Post by drgary »

dustin360 wrote:quick side note: did you check to see that the thermocouples were calibrated correctly before installing them in the roaster? When I bought a bunch of thermocouples off ebay when I got the quest, and after hours and hours of trying to figure out my weird readings(not spikes, but inaccurate temps) I realized I never checked the probes in boiling water. So I did. And ALL of the cheap thermocouples I bought were total crap, not a single one was giving me 212 or even close. (also my analog thermometer that came with the quest was off, so I know I always check thermometery before applying it)


Instead of dismantling my TC installation I ordered a duplicate TC from my eBay supplier. Sure enough when holding the tip just beneath the surface of rapidly boiling water the reading was 207.9 F. Now I'll adjust all of my Hottop readings with these TCs. Thanks, Dustin!
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

rgrosz

#62: Post by rgrosz »

My eBay TC probes look like the first photo in this message:
Troubleshooting Electrical Noise with Roaster Thermometer [Solved]

I have some grounding issues, based on my results from Artisan. Everything looks fine until I load the greens in my HotTop. Then the readings start jumping around slowly (at first). As the roast progresses towards first crack, they become quite erratic. It appears the BT / ET values are moving in opposite directions.
LMWDP #556
Life is too short to drink bad wine - or bad coffee

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yakster
Supporter ♡

#63: Post by yakster »

When I set up my La Peppina espresso machine and PID at work, I noticed that the brew temp readings would really jump when I ran my little desk fan. I ended up moving my fan to the other side of my monitor which resolved the problem in short order. The electro-magnetic field of the fan motor was especially troublesome.
-Chris

LMWDP # 272

rgrosz

#64: Post by rgrosz »

I ripped out my old thermocouple setup and started over. After the HB-Weld cured overnight, I tested this using my fingers as the heat source.

Apparently I damaged one of them, so I ordered a replacement on e-bay. This time, I got something from the USA, so I won't have to wait until March to get it. Some day I'll get this working properly <sigh>
LMWDP #556
Life is too short to drink bad wine - or bad coffee

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fransg

#65: Post by fransg »

I think in my case (probes on the espresso machine lever group head) flushes (like when I start up the machine cold and heat up the group) initiate spikes and on one occasion I noticed the spike coincided with something in the machine clicking on/off. The heater maybe but that clicks off/on all the time, and a little water from the mains is allowed in every now and then without predictable spikes.

I bought fresh new batteries for the Amprobe to make sure that it wasn't old batteries there, and I have ordered 4 new T type probes, the simple ones with the naked beads at the end, so I will have a stock of them in case I want to ry replacements.

I ordered them from TCdirect:
http://www.tcdirect.nl/deptprod.asp?dep ... ch=401-321

They have international branches:
http://www.tcdirect.com/

Dan Bollinger

#66: Post by Dan Bollinger »

Another way to deal with RF noise, if that's what this is, is to install a choke, aka ferrite toroidal inductors. They are 30mm x 5mm. Go to WikiPedia and search toroidal inductors for the formula to determine the number of wraps, or use the trial and error method. I have a hundred, so if you want one or two send me your mailing address. In exchange, you promise to post your results here.

They are 30mm x 5mm and look like the top one in the photo. Go to WikiPedia and search toroidal inductors for the formula to determine the number of wraps, or use the trial and error method.

rgrosz

#67: Post by rgrosz »

rgrosz wrote:I ripped out my old thermocouple setup and started over. After the HB-Weld cured overnight, I tested this using my fingers as the heat source.

Apparently I damaged one of them, so I ordered a replacement on e-bay. This time, I got something from the USA, so I won't have to wait until March to get it. Some day I'll get this working properly <sigh>
I did not have success back in March using the cheapie eBay thermocouples.

Based on the instructions in this thread, I purchased some Omega XCIB-K-3-5-3 thermocouples ($40 each). I can confirm that this was my final solution.
LMWDP #556
Life is too short to drink bad wine - or bad coffee