Hi I am a novice and am looking for a loadcell application ic and i landed upon ads1232. I got a doubt regarding the voltage reference for ads1232. If i am using bipolar supply of +/-5v for my load cell, to the ads1232 vrefn and vrefp pins can i directly connect -5v to REFN and +5v to REFP? Any other special considerations to be taken care of?
Badri,
Welcome to the forum! The maximum voltage supply for the ADS1232 is 5V, so the maximum reference must remain within 5V. You can not apply any signal or reference voltage below ground as this is not a bipolar supply part. You can excite the load cell with +5V and connect the other end to ground. And you can also use the same +5V for your reference (REFP) and connect REFN to ground.
You may find the ADS1232REF, which is a reference design, helpful with seeing an example on how to connect the system. You may also find the following link helpful with designing your load cell system:
http://www.ti.com/ww/en/industrial/sensors/weigh/design.html
Best regards,
Bob B
hi bob,
Thanks for the help.
Just to Confirm, i'm thinking of applying 5v for excitation and also vref as suggested. Will a 5v supply made out of 7805 will suffice?
You can use the 7805, but the output is a bit noisy. You will probably want to place a large capacitor on the output to filter some of the noise. It is always best to use all high quality and low noise components in your system, however the higher cost can make this difficult.
One area that is very critical is the PCB layout. A ground plane is most ideal. Also, make sure that the analog and digital ground pins are connected directly together near the ADS1232.