BCS Temp Probes....Ugh!

[calebstringer]

Hi everyone. I need help..... I have a BCS-462 system. Most of the components came in a kit from eBrewSupply. I have their 3 wire, Male XLR connectors mounted in the panel, and Auber Instruments Tri-Clamp Liquid tight RTD Sensor, with their braided cable. Here's a link to the sensor...

http://www.auberins.com/index.php?main_page=product_info&cPath=20_15&products_id=267

Anyways, I called eBrewSupply and asked how to wire their 3 wire to the BCS. I really didn't the easiest answer, but more or less was told wire one red to the temp input, and the clear jacketed wire to ground. So I kept it consistent throughout wiring all 8 (fermenter, brite tank, glycol chiller, 3 vessel BH, plus room for 2 more fermenters Hook up my fancy tri-clamp sensors, and nothing. Do some digging and find out I need to change coefficient A,B, & C to match the non BCS sensors. Get that nailed down, and it got it working, sort of. Temp sensors GENERALLY read 20ish degrees high, and they fluctuate in 5.3* increments. So as for today, ambient temp was 85 or so, and they kept fluctuating between 104.3 and 109.6.

I swapped which wire was input, which was ground, swapped the reds, wired the reds together, no go. It keeps reading the same, and making the same big swings.

I put one in a 35* beer, and it read, you guessed it, 104.3.

I don't know what to do. Im beyond frustrated that this is holding me back from being able to brew... Any ideas on solution? And yes, I do have a ground wire going from the temp probe block of the BCS to the ground of its power source.

FYI, the coefficients I'm now using are:

A: 0.0369
B: -0.009117832
C: 0.0000895868

I even had an engineer verify them!

Thanks everyone

Caleb

 

[BrunDog]

You aren't going to like hearing this... but these sensors will not work with the BCS. The BCS uses thermistor based probes. The Pt100 (aka RTD) probes you listed are different. These nominally have a resistance of 100 ohms, and the Thermistor probes have usually 10,000 ohms nominally. The slopes/gains are different too. Plus RTDs are typically 3 or 4 wire, where thermistors are 2.

That said, if you love the physical builds of the probes you are using, you can swap out the internal sensor. You need tools and good soldering skills. I did this with my BCS (and now use the same probes with BruControl) with great success. If you want to go that route, I can look up the thermistors I used - though if you search Cantherm on this forum you might find a post I put up with the model.

 

[calebstringer]

Thank you BrunDog. You confirmed what I thought. Well, that's what I get for being impatient and trying to find an "alternative" when brewers hardware and ebrewsupply were out of stock. I ordered 3 BCS TC from BH and will put XLR connectors on them. Hopefully I'll get them Monday, but who knows with the holiday. I really want to brew Thursday....