Temperature fluctuations

[Danimal39]

So, I'm out of ideas, and want to see if anyone has anything else clever I can try. We are a new microbrewery in Denver, CAUTION: Brewing Company, and we are planning to use a BCS in the brewery. Right now, we are looking to control glycol solenoids to our 13BBL fermenters with the BCS. Trouble is, we're running into an issue with temperature swing.

The log graph is below, and we see this kind of behavior almost all the time, but not always. The BCS is wall mounted in a closet inside an old alarm system enclosure. The fermenters are about 50ft away, with their corresponding solid state relays mounted in another alarm system enclosure, also wall mounted. We are located in the middle of a strip warehouse complex, but we are surrounded on two sides by concrete walls and one side by a fire rated wall neighboring an empty unit. So, what we've done to troubleshoot so far:

- connect probes directly to the BCS, probe is in closet, works fine
- connect probes via 50' Cat6 shielded ethernet, probe is outside closet, temperatures swing
- connect probes via 50' shielded 24 gauge speaker cable from Radio Shack, probe is outside closet, temperatures swing.
- connect probes via 6' Cat6 shielded ethernet, probe is outside closet, temperatures swing.
- Turned off power to everything in the brewery except for the closet powering 5 port Netgear switch and BCS. No luck.
- a number of different wiring schemes to eliminate cables from barrier strips and such, but it's now obvious that the connecting cable (Cat6 ethernet) between the enclosures is the issue.

Could something be causing so much interference as to do this to different shielded cables? The cable run is not near any conduits, compressors, or motors. I've had the cable on the floor and it still does the same thing. Surprising anything over the air and nowhere close to the cables can do this. I'm probably getting 1.21 gigawatts pulsating through my body whenever I'm at the brewery.

The last resort is to relocate the BCS, which I don't want to do...so, are there ways to change the configuration so I can get better data from the probes? I'd hate to have the solenoids on our tanks go haywire because of the fluctuations in apparent temperature. Ideas or anything I haven't tried would be appreciated! A free beer to anyone in the Denver area who can figure out what's going on with this.

probe.jpg (83.44 KiB) Viewed 5408 times

Danny Wang - Overlord/Head Brewer
CAUTION: Brewing Company - Denver, CO
970.315.BREW

[JonW]

What is your wiring usage of the CAT-6? e.g. is each probe on a "pair" or other wire allocation? Using a shared ground?

Does your Cat-6 have a drain wire? If so, are you grounding it at one end or both ends?

If not already doing so, each temp probe should be on it's own pair. The twists in the cable help to eliminate crosstalk and interference.

Are you running the relay control (outputs from BCS) in the same cable as the temp probes?

It is very interesting how consistent the temperature swing is in both timing and value.

[ECC]

One thing to try is to attach the GND pin of the BCS to ground. We've seen cases where ground loops can cause behavior similar to this.

Another culprit is if you're using 3rd party temperature probes. The BCS ships with default temperature probe coefficients for our probes, and need to be updated to match other sensors.

[Danimal39]

Thanks for the suggestions, I'll play around with grounding configurations and see if this issue goes away. I did at one point use one cat6 cable for both probes, but for troubleshooting I've just tried getting one probe to behave correctly. The cat6 cable does have a drain wire which is not grounded anywhere, and I'll definitely try that.

When I only have one probe connected, I have tried to run on a single pair (orange, orange/white) directly back to the BCS, and still the same result. The graph I attached in my original message was taken when I had a single Radio Shack speaker cable attached directly to the probe, going back to GND and Temp4. The ECC itself does not have any GND pins attached anywhere except to the probe. Perhaps that's where my issue lies? And I'm using the probes I bought from you. Thanks for the help, I'm sure it's a wiring issue, interference just doesn't seem like the cause of this!

--
Danny

[gbrewer]

Is there any chance this could be caused by dirty electricity? Any chance of coincidence on when it started? Perhaps there is something noisy on the circuit? Plug the bcs 460 into a ups to rule it out.

[Danimal39]

JonW got the winning answer! As soon as I grounded both ends of the drain wire in my ethernet cable, all my readings settled down. Thanks for everyone's suggestions and tips! JonW, if you're in Denver, look us up, we owe you a beer.

Danny Wang - Overlord/Head Brewer
CAUTION: Brewing Company - Denver, CO
970.315.BREW