Hey Setu,
National Instruments does not supply a cable or method to connect the SC series devices to SCXI modules. You can connect up to 4 SC-2043s to one DAQ card that is not connected to a SCXI chassis. There fore, if you had 2 daq devices and 8 SC-2043 you could hook up 64 quarter bridge strain gauges.
However, I would not recommend this. I recommend getting 8 SCXI 1520s. These modules are far superior to the SC modules. The SC series only has a gain of 10, which is pretty low and it has no filtering and the excitation is 1.5-2.5 volts (controlled by a potentiometer) and it does not have any gain correction or null offset. The 1520 features go on for miles. I promise that you will be much happier with the 1520s.
I hope this helps.
Joshua
