Ramesh Reddy:
I just recently finished working on an 8052 project that was a device that measured pressure in a hand grip using a strain gauge detector (same as you have from a load cell) wired in a full bridge configuration, On this design the OPAMP that was used was the Linear Tech LT1014. This device is a quad device that was hooked up as follows:

Each side of the bridge was buffered through one section of the LT1014 wired as a unity gain inverting buffer. The buffers job is to remove the input impedance of the diff amp from loading the bridge in any way. (in this design the input impedance to the diff amp itself was around 450 ohms. The outputs of these two buffers then drove into the 3rd section wired up in a full diff amp configuration. The power supply was +5V and ++ side of diff amp was setup so that the reference voltage was at 2.5 volts. (Note that the 4th section is left unused so that stray noise does not make its way into the amplifier configuration. The output of the diff amp section was used to drive an LT1297 12-bit A/D converter. This converter has a serial interface to read the conversion results into the microcontroller. This also helps keep processor noise out of the analog section. The gain of the diff amp was selected so that about 120% of the usable range of the bridge output would drive the A/D input through the full input voltage range of 0-5 volts. In general I do not recommend using an onboard A/D converter for reading this type of instrumentation because you cannot afford to lose the 2 1/2 bits that is so typical of onboard 12 bit A/Ds.


Hope this helps. (If you want more detail just post back).
Michael Karas