Temperature reading issues

[clintoffutt]

I have a BCS460 and BCS462, both firmware 3.4.5, in the same control panel. The BCS460 is reading wrong temperatures, almost exactly 10* high. If I take a probe, all from Brewer's Hardware, and swap it from the 460 to the 462, it will read correctly on the 462, again almost 10* lower than the 460. I have copied the coefficients from the 462 and pasted in the 460 just to be sure those match. I am using A=0.001137155, B=2.3259496e-4, and C=9.540003e-8 like is posted on the Brewer's Hardware website, but of course the units seems to slightly round? and the readings look a little different on the system settings due to scientific notation....

The problem is consistent across all temp. inputs on the BCS460, and consistent across all probes I use. I think I have 12 probes and have tried probably 10 just for reassurance. If I go into the temperature calibrations on both units, again regardless of which probes, the 460 is showing resistance values of ~8K compared to the values in the 462 reading ~12k. These values are again consistent across all temp inputs on the 460 and across all inputs on the 462. I have both BCS units tied to the AC system ground.

I know the 460 is wrong, simply because it's reading ambient temperature in our brewery at about 80*, which it is not, but also comparing to a NIST calibrated thermometer, analog thermometers in our brewery, hydrometer thermometers, etc.

I have no desire to upgrade firmware, nor at this point to I want to reset a unit, or even restore to defaults if there is an obvious fix outside these options. The 460 has always read these values, but has not been an issue we have addressed because we are just now starting to use a BCS in the brewhouse.

[JonW]

Below should be the default coefficients for the Brewers Hardware probes. Do you have a link where you pulled the others from?

A= 0.0011371549
B= 0.0002325949
C= 9.5400029999e-8

I don't have any obvious answer on why the two systems are reading the probes differently. I know you don't want to hear this, but the first thing you should do is reset your system just to make sure there isn't a software quirk somewhere that is affecting this. Also, if you want to stay on the 3.x software, I would highly suggest moving to the latest 3.71. Starting in version 3.7, the firmware is setup to use the Brewers Hardware coefficients by default.

You may also want to perform your own probe calibration for your system. There are several threads here on the forum with details on how to take the measurements. http://forum.embeddedcc.com/viewtopic.php?f=6&t=10

[clintoffutt]

I believe our coefficients are equal, just notated differently. I had my figures from the Brewer's Hardware "instructions" page...http://www.brewershardware.com/temperat ... tions.html

I will sure try to reset the 460. Does this reset clear all system settings? HMI, temp coefficients, etc? Or does it just restart the unit and keep all settings? It seems like that version had some bugs with the reset button.

And we will look into the firmware updates as well, but I am mostly wondering if this seems like a hardware issue with the 460 not reading the impedance on the temperature probes correctly. Or a fundamental electrical wiring issue.

[brahn]

Yup, those coefficients are the same.

The reset would clear all system settings. You can back them up first from the settings page and restore them after the reset if you like. Just test the probes first to see if they read what you're expecting.

Since the error is so consistent, I would probably try re-calibrating the probes to see if that solves the problem. The instructions are here: http://forum.embeddedcc.com/viewtopic.php?f=6&t=10


I know you're using the 3.x firmware, but for anyone running the 4.0 firmware who finds this thread forum user bbrally built a really nice tool to help with calibration here: http://bbrally.from-ca.com/