Bar100 Keller PA Sealed Gauge

[marcob (marco bernardini)]

Hi, reading the datasheet of the Keller PA 7LD, they wrote: “PA: Sealed Gauge. Zero at 1,0 bar abs”.
Then looking at your library on GitHub I found that you are adding 1.01325 Bar . Why adding 1ATM and not 1 Bar ?

[EliotBR (Eliot)]

Hi @marcob, welcome to the forum!

@marcob

looking at your library on GitHub I found that you are adding 1.01325 Bar . Why adding 1ATM and not 1 Bar ?

Looking at the Keller 4LD…9LD Datasheet (notes (3) and (4)) from our Bar100 product page, and the Keller 4LD…9LD Communication Protocol Manual (P-mode types: section 5.1, page 12; examples section 4.2, page 9) that we link to from our GitHub it seems like an error has been made in assuming that note (4) applies to the whole 7LD range as opposed to specifically being for the relative pressure mode-type specifically.

P-mode type PA is the only one with a possible pressure range of 0-100 bar, and is also the ‘Sealed’ sensor, so the Bar100 has to be using it, in which case the offset in our code is likely incorrect. I’ve brought this up internally and raised a GitHub issue for it here.

[marcob (marco bernardini)]

Thanks! Another question:
if you put the sensor on the bench, do you have a stable reading up to the 3rd decimal digit (mbar)? I’m observing a jitter in a range of 4 mbar.

[EliotBR (Eliot)]

@marcob

if you put the sensor on the bench, do you have a stable reading up to the 3rd decimal digit (mbar)? I’m observing a jitter in a range of 4 mbar.

I don’t have access to one to test with, but given our Bar100 technical details specify a pressure resolution of 3mbar that would seem consistent with our documentation.