Anbody familiar with BFSL?

[USMCPMEL]

I was working on a gauge today and it was way low like 4% but because it is linear so according to BFSL it is in. Anybody have any thought on the subject?

[microwave-kevin]

Sounds like zero or span is off if BFSL is 4% low

[USMCPMEL]

Zero was off. I adjusted it. I knew that. What I am asking about is the concept of BFSL. How it makes it ok to be off by    -1030 PSI and it still appears to be in tolerance because of the graph.

[microwave-kevin]

Not familiar with the procedure you are using but wouldn't BFSL only be a linearity check / performance test, item could easily pass linearity but fail value (for example % of span and % of FS)

[USMCPMEL]

That is pretty much what I am trying to figure out. It seems to be that way. We use the program to tell us if it is within tolerance or not.

[jimmyc]

http://hotmath.com/hotmath_help/topics/line-of-best-fit.html

[calgod]

Most pressure transducers have a BFSL spec. When calibrating to a BFSL spec you are checking the linearity. However, most transducers that have the BFSL spec also have a zero offset spec and full scale output spec. So, theoretically it could pass the BFSL and fail the zero and full scale output spec's. I have seen these mostly on transducers i.e. pressure and strain. They use the BFSL because of the design of the bridge.

If you want more info google the subject it is pretty in depth and far to lengthy for me type out. Also, consult the mfr manual on the item. Most of the time they have a theory of operation and also explain the reasoning behind the BFSL.

You stated that this is a "gauge". What type of gauge is it? I hope not an analog? I have seen this spec more and more on digital pressure gauges. But, usually they have other spec's containted with in.

[USMCPMEL]

I meant transducer.  have only seen this on transducers.