Miniature Analogue Amplifier - full bridge load cell

Thread Starter

kevinnas

Joined Jul 31, 2017
77
Hello.
I would like to make a miniature analogue amplifier something like the ones below except I only need 0-10V output & to be used by load cells around 1-5kohms, 2mV/V sensitivity. Typically 5V or 10Vdc excitation, 3V to 40Vdc supply (flexible, could be anything).

http://www.appmeas.co.uk/ica-miniature-analogue-strain-gauge-load-cell-amplifier.html
http://www.mantracourt.com/products...conditioners/miniature-strain-gauge-amplifier

Anyone with any ideas or rough sketch of how the schematic could look like? and what the components I could use for good performance?.
I would appreciate any help, I do not expect it to be done for me but any help would be appreciated or a pointer in the right direction. I am looking for an analogue solution for the mean time.
 

Thread Starter

kevinnas

Joined Jul 31, 2017
77
Take a look at this.
Something there should work for you.
Hi. Thanks for the reply. I have been looking for a while at all those solutions but I am not quite sure which to go for which is similar to the ones on the link above. I notice on the links I sent you, their solution has two pots & some transistors & Caps and a gain resistor but none of the solutions have similar components? most of the solutions on there us something like an instrument amp which I do not think was used on the one I sent which is why I am confused as to which solution gives the simplest solution for a 0-10V output.
 

Thread Starter

kevinnas

Joined Jul 31, 2017
77
How about this one.
Instrumentation amps are commonly used for such applications.
Thanks that looks good. The question I have is: How do I make this into a 0-10V output? It just seems like you have an input of 8-30V, adjustable gain and offset, Bridge excitation of 5V which are perfectly fine, The it says "this design allows the output voltage to be greater than the range desired at some circuit gains and bridge signal levels" but I am not sure how to turn it into a 0-10V output
 

Thread Starter

kevinnas

Joined Jul 31, 2017
77
Another thing is the Temperature which is rated at -40degC to 85degC compared to the 0-50degC In that solution..The AMP04 Itself is rated to -40-85degC so which components might be reducing this down to 0-50degC and what can I do to keep the rating to -40-85C?
Is the amp04 better than other IA's like INA25P etc? how do I determine which IA to use?
 
Last edited:

crutschow

Joined Mar 14, 2008
34,285
what can I do to keep the rating to -40-85C?
Just make sure all components are rated for that temperature range.
s the amp04 better than other IA's like INA25P etc? how do I determine which IA to use?
The AMP04 apparently is a top of the line device.
You look at the important specs such as input voltage offset, supply voltage/current, cost, availability, etc. and decide what will be adequate for your requirements.
Since you haven't stated those, I can't make any specific recommendations.
There likely are quite a few that will meet your needs.
 

Thread Starter

kevinnas

Joined Jul 31, 2017
77
Just make sure all components are rated for that temperature range.
The AMP04 apparently is a top of the line device.
You look at the important specs such as input voltage offset, supply voltage/current, cost, availability, etc. and decide what will be adequate for your requirements.
Since you haven't stated those, I can't make any specific recommendations.
There likely are quite a few that will meet your needs.
I am using the designs in the original post as my benchmark. E.g
http://www.appmeas.co.uk/ica-miniature-analogue-strain-gauge-load-cell-amplifier.html
So anything that meets or exceeds that will be perfect.
 

Thread Starter

kevinnas

Joined Jul 31, 2017
77
That involves more analysis than I am willing to do, so you will have to do that yourself.
Or buy the already built device.
That's fine, thanks for your help I appreciate it. buying an already made one is not an option because I will not learn anything from it which defeats the whole point.
 

crutschow

Joined Mar 14, 2008
34,285
I will not learn anything from it which defeats the whole point.
Then you can learn a lot by analyzing the circuit and determining which parameters are important to your application and which are secondary.
That's a major part of designing any circuit.
 
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