Pressure gauge schematic

[Vincent Himpe]

I'm looking for a schematic of a pressure gauge that uses a load cell (
wheatstone bridge )

Gauge measures between 0 and 4500psi ( 300 bar ) I got the load cell

problem is signal conditioning. full scale is only 100mV. and i need to
amplify this to 2.25 volts ( so 0.5 millivolt is 1 psi. the gauge gives me
)

The opamp circuits i made all tend to drift and are sensitive to noise due
to the high gains involved . plus ther eis the problem of the common mode
voltage.

I know tere are special instrumentation amps available but those cost an
arm and a leg. Does anyone have a schematic on how to build this using
regular god opamps like op177 ?

 

[Ross Herbert]

On Sun, 29 Aug 2004 09:13:27 GMT, Vincent Himpe
<vincent_himpe@hotmail.com> wrote:

|I'm looking for a schematic of a pressure gauge that uses a load cell (
|wheatstone bridge )
|
|Gauge measures between 0 and 4500psi ( 300 bar ) I got the load cell
|
|problem is signal conditioning. full scale is only 100mV. and i need to
|amplify this to 2.25 volts ( so 0.5 millivolt is 1 psi. the gauge gives me
|)
|
|The opamp circuits i made all tend to drift and are sensitive to noise due
|to the high gains involved . plus ther eis the problem of the common mode
|voltage.
|
|I know tere are special instrumentation amps available but those cost an
|arm and a leg. Does anyone have a schematic on how to build this using
|regular god opamps like op177 ?
|


Possibly something like http://www.linear.com/pdf/lt1250.pdf

 

Vincent Himpe <vincent_himpe@hotmail.com> wrote:

But i found a company that sells these things to
individuals.

Making your own dive computer? Make sure you sign off on all the
"life support" documentation from each and every one of your
vendors...

 

[Vincent Himpe]

William P.N. Smith wrote in news:qmo3j0hugj11g8ki0ok14etnt5qnf36iad@
4ax.com:

Vincent Himpe <vincent_himpe@hotmail.com> wrote:
But i found a company that sells these things to
individuals.

Making your own dive computer? Make sure you sign off on all the
"life support" documentation from each and every one of your
vendors...

nope. fully automatic nitrox/trimix blender and analysers

 

Vincent Himpe <vincent_himpe@hotmail.com> wrote:

William P.N. Smith wrote:
Making your own dive computer? Make sure you sign off on all the
"life support" documentation from each and every one of your
vendors...

nope. fully automatic nitrox/trimix blender and analysers

Yow! More power to you, but make sure your {business,life} insurance
is well paid up, and for a couple of orders of magnitude more than you
think you need! 8*}