creating a load cell scale with tare

[Valkyrie]

I am running version 7.1 and I need to create a VI to read three load cells which are used in our wind tunnel to measure drag, lift and pitch moment. I can read the data, but I need to be able to zero the reading when a new or different airfoil is placed in the tunnel or to tare the weight out to zero and read the new wieght.

[Linkster]

take the voltage reading when the air foil is placed in the windtunnel and store it as an offset.  then subtract this offset off from future readings and it should bring it back to zero