Are these 2 wiring setups identical ? For me I think it will be easier to wire it up with the modified (top left) version if it is the same ?


Thanks

 

hi nite.
When you say load cell, do you mean a strain gauge 'element', or half bridge.?

Look at page #5 of this PDF.
E

 

hi nite.
When you say load cell, do you mean a strain gauge 'element', or half bridge.?

Look at page #5 of this PDF.
E

Its a loadcell / strain gauge : https://www.robotgear.com.au/Product.aspx/Details/1728-Load-Sensor-50kg
I got the original diagram online to turn the 3 wire output into a 4 wire output required for my INA122 amplifier.
I currently have it all wired up with a 4 wire loadcell and this new loadcell is a straight replacement for it.
That PDF you linked means nothing to me

 

hi,
Checked your link, its a 'half bridge'.
So as you say you need two resistors adding across the Vext wires Red and Black.
The junction of the two resistors is connect to A-.,, the White wire to A+.

Its important that the two resistor are exactly the same value, otherwise you get a large offset reading on the Scale.

The usual way to get around this is to have two identical resistors connected to the ends of say a 100 ohm trim pot.
The wiper of the trim post is connected to A-.
So when there is no weight on the scale the trim pot is adjusted to give a zero weight reading on the scale.

Do you follow OK or would a sketch help.?
E

Added: Circuit option.

 

I just need to know if both of those diagrams are the same - I have no knowledge of electronics and just going to copy the bottom one (which is correct for my application) but would be easier for me if I can do it the same as the top one.
thanks again

 

hi
Either would,
But remember the caution about the resistor values being matched, else a big weight offset error.

Keep the wires as short as possible, to avoid electrical noise pick up on the weighing signal lines.

E