Calculating pressure drop speed in automation system

Question

I have a problem. How would you calculate pressure drop speed, if you only get data from a manometer? I need a specific drop speed in [bar/h], and can only read pressure in [bar]. I can't think of a way I can do that in my software, except for sampling measurement in some sample rate and than use dp=p(i-1)-p(i). Thanks in advance.

Answer 1

I agree with you, that the only way to get a pressure rate over time would be to sample the pressure, and calculate the rate that would be meaningful to your user. This could be a rate between two samples, or the "best fit" line of a sample using linear regression. Any rate is really a slope.

I don't have enough REP to post a picture, so see this best fit line example here:

http://2.bp.blogspot.com/-d4LyN1FgyYc/T54PTebg3xI/AAAAAAAAYa8/aBNyp_pC7vQ/s1600/weightLossLinearRegression.JPG

You can think of it in terms of your car. Your car provides you an instantaneous rate (Mi/h) and some newer cars will provide a rate over time, in the form of your average speed since you last reset the logging.