Interpolation using GROWTH function?

[victurbo]

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?

[Bernard Liengme]

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" <[email protected]> wrote in
message news:[email protected]...
>
> 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
>

[Tushar Mehta]

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 <[email protected]>,
[email protected] says...
>
> Background: I'm a instrument technician trying to use Excel to scale a
> nonlinear device which streams a measurement (ultimately, force in
{snip}

[MrShorty]

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.