Are you expecting a linear response? If so...

We know the following:

> 6500 Hz - 2500 TDS
> 400 Hz - 30 TDS

Setting that up as equations in the form y=3Dmx + b we get:

2500 =3D m*6500+b
400 =3D m*30+b

Now just solve those two equations for 'm' and 'b' (a simple exercise for
the reader) and you have what you need.

~ Bob Ammerman
RAm Systems

> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
> Of Ravi
> Sent: Friday, August 22, 2014 11:49 AM
> To: Microcontroller discussion list - Public.
> Subject: [EE] Formula for calibration
>=20
> Hello All,
>=20
> I hope that I have the right tag. I am a bit rusty and hope that some one
> would point me in the right direction.
>=20
> I am designing a TDS meter.
>=20
> For a TDS of 2500, I get a frequency of 6500 Hz and for a TDS of 30, I ge=
t
a
> frequency of 400 Hz.
>=20
> My 2 points of calibration are those below.
>=20
> 6500 Hz - 2500 TDS
> 400 Hz - 30 TDS
>=20
> I need a formula to calculate the intermediate values based on the
incoming
> frequency.
>=20
> Thanks in advance
>=20
> Cheers
>=20
> Ravi
>=20
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist

--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.