Quest M3 BT thermocouple problems - Page 3

February 14th, 2014, 9:48 pm

I've always wondered how people could possibly have noise problems with TCs; but I've always used either battery powered ones or ones connected to high end PID controllers

I'll have to keep this in mind for the next time someone has gremlins

http://users.rcn.com/erics/ · #22: Post by **erics** » February 14th, 2014, 9:58 pm

Jeremy -

I would contact the tech support group at Amprobe and refer them to this thread or explain the situation. Based on past experience, they are very responsive.

I would (obviously?) regard this as a meter and/or meter AC power supply problem and nothing else. It is, most definitely, NOT a thermocouple issue.

February 14th, 2014, 10:23 pm

Good call, Eric. It seems like I'm not entirely alone in this situation. I know roasters are likely a small subset of Amprobe's market, but I bet they'd like to know about this.
Jeremy

#24: Post by **lukas** » February 16th, 2014, 3:21 am

Tristero wrote: Lukas, I may have been misleading in my original post. I get what you're saying. I've roasted on some open-front sample roasters where the temps were way off from what I would have expected. The important thing is to use the sensory milestones to track the roast, right? I get it. I'm less obsessed with knowing what the "absolute" temperature is than I am curious as to why the thermocouple behaved so inconsistently. It just piqued my diagnostic curiosity to investigate the source of the variation. Mostly, I'm a cheapskate who spent $80 on thermocouples that gave weird, unreliable readings and this made me want to understand why it was happening.

Hi Jeremy, this rant was really not specifically aimed at you, your post just was a welcome excuse to post what I had in mind for a while already. Absolute numbers get tossed around all too often as well as references to the "right" placement of thermocouples as well as the "right" temperatures at which this or that happens.
Glad you have it sorted out, these transient thermocouple issues can drive one nuts indeed!

All the best,
Lukas

#25: Post by **lukas** » February 16th, 2014, 3:24 am

Eric,

I think it's neither nor - it's a simple potential difference between the roaster and meter. That's really nearly unavoidable in roasters with motors. The solution is either ungrounded thermocouples or slightly sophisticated and well thought-through grounding methods.

Lukas