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#1
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Interpolation using GROWTH function?
Background: I'm a instrument technician trying to use Excel to scale a nonlinear device which streams a measurement (ultimately, force in pounds) to a .CSV file. The Data is formatted as a raw, unscaled number in one column and a adjacent timestamp in another column. If the sensor was linear I could simply multiply that raw number by the appropriate scaling factor to get pounds but this particular sensor is not. If I take sample readings with known standard weights at regular intervals alongs the device's full scale and plot Pounds (x) and the device output (Y) can I use the GROWTH function to create a formula which will then automatically condition/scale/interpolate the devices output in my spreadsheet chart when I'm using it out in the field? I know GROWTH can plot points in the future but can it determine points in between? Is this the right function for this job or would something else be more appropriate? -- victurbo ------------------------------------------------------------------------ victurbo's Profile: http://www.excelforum.com/member.php...o&userid=27162 View this thread: http://www.excelforum.com/showthread...hreadid=466735 |
#2
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I am a scientist and this is what I would do:
Make a plot in Excel of Known Pounds (x-axis) against Measured Values (y-axis) Add a polynomial trendline (up to 4 powers) to find a good fit, note which power is used Use LINEST with that power to get these values into cells (see my website) Use the LINEST values to compute the Actual Pounds Contact me a personal email if more details needed best wishes -- Bernard V Liengme www.stfx.ca/people/bliengme remove caps from email "victurbo" wrote in message ... Background: I'm a instrument technician trying to use Excel to scale a nonlinear device which streams a measurement (ultimately, force in pounds) to a .CSV file. The Data is formatted as a raw, unscaled number in one column and a adjacent timestamp in another column. If the sensor was linear I could simply multiply that raw number by the appropriate scaling factor to get pounds but this particular sensor is not. If I take sample readings with known standard weights at regular intervals alongs the device's full scale and plot Pounds (x) and the device output (Y) can I use the GROWTH function to create a formula which will then automatically condition/scale/interpolate the devices output in my spreadsheet chart when I'm using it out in the field? I know GROWTH can plot points in the future but can it determine points in between? Is this the right function for this job or would something else be more appropriate? -- victurbo ------------------------------------------------------------------------ victurbo's Profile: http://www.excelforum.com/member.php...o&userid=27162 View this thread: http://www.excelforum.com/showthread...hreadid=466735 |
#3
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Also, check my response to the same request at the mrexcel.com web
site. -- Regards, Tushar Mehta www.tushar-mehta.com Excel, PowerPoint, and VBA add-ins, tutorials Custom MS Office productivity solutions In article , says... Background: I'm a instrument technician trying to use Excel to scale a nonlinear device which streams a measurement (ultimately, force in {snip} |
#4
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Short answer: yes, GROWTH can handle interpolation as well as extrapolation. GROWTH uses an exponential model [y=A*exp(Bx)] to correlate the data. If this type of model will represent your data well, then GROWTH should work fine. -- MrShorty ------------------------------------------------------------------------ MrShorty's Profile: http://www.excelforum.com/member.php...o&userid=22181 View this thread: http://www.excelforum.com/showthread...hreadid=466735 |
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