Temp Probe Wiring

[Broph]

Check out http://www.embeddedcontrolconcepts.com/ ... 3e9a#p2756 ...

Have you confirmed that the coefficients into the BCS-460 setup are (from http://www.brewershardware.com/temperat ... tions.html) :

A= 0.001137155
B= 2.3259496e-4
C= 9.540003e-8

also on the same page (above) Binding this wire to your system ground can help reduce interference when running spark igniters or if the wires run near your pumps.

[BentTwigBrew]

I calibrated and entered my own coefficients and it reads spot on at boiling and 32*.

The last post in that thread makes me believe something might be wrong with the probe itself. I'm not sure if take the probe apart I will be able to successfully put it back together. I'm going to go ahead and order a probe from ecc. Does anyone know if that probe will fit in the brewers hardware thermowell??

I will also try connecting the Unshielded ground and see if that helps.

[ECC]

Grounding the unshielded wire on one end will have the benefit of giving you additional noise rejection. Although just having it gives you some benefit.

Also, you may try grounding the BCS.
http://www.embeddedcc.com/wiki/index.ph ... ng_the_BCS

If you suspect a bad probe, I'm sure Derrin over at BH will make it right. Do you have a 2nd probe that you can swap in to isolate the problem? Make sure to keep the same long run of wire, since the problem could very well be there. Make sure to update the coefficients if a different probe type is used.

Our probes are the same diameter as the BH probes, 1/4".
http://www.embeddedcc.com/wiki/index.ph ... rmowell.3F

[BentTwigBrew]

Well I tried grounding the unshielded wire last night and at first seemed to solve the issue. The resistances were reading very steady....but then the temp took off again. Now the problem actually seems to be worse because now even with the probe out of the thermowell, the temp does not return to normal. I also have the BCS grounded...

I unplugged the refrigerator and the glycol compressor to see if they were causing interference. The fridge did seem to have some affect when the compressor would kick on, but I don't believe this is what is making the temp reading increase steadily until it hits like 200*.

I am going to assume something is wrong with the probe. Derrin's are backordered until 1/31 so I will order one from ECC tonight. If that solves the problem, I'll see if Derrin will hook me up with a new one.

To be continued....

[Broph]

What size was the temp probe? I have an extra temp probe from Brewers Hardware I'd be willing to send to you if it would help. It's an 8" probe with m8 connectors and extra cabling to run back to the BCS.

BrewersHardware8_m8.jpg (74.3 KiB) Viewed 5413 times

Tom

[BentTwigBrew]

Wow! Thank you for the offer! Super nice of you, but I went ahead and bought 2- 4" probes from ecc last night and already got the tracking number. Figure I would get two to completely rule out a bad probe. Will definitely find a use for it in the future. If it does prove to be a bad probe I'll let Derrin know. At this point I really hope this is the case because I am at a loss...

Thanks for helping me work through this!!!

-Karl

[BentTwigBrew]

I received a new probe from ECC last night and swapped out my other probe. 24 hours later the temperature readings are holding steady. I think I can assume I was using a bad probe. Hopefully this issue won't come up again. Need to contact Derrin and see if he will swap out the bad one for a new one. Thanks Broph and ECC for the advice.