Thanks Kai.

Your suggestion for using individual IAs to amplify the load-cell signals, AND to sum them up digitally translate into the same thing (almost) as what Erik recommended (By using a 4x channel ADC and summing signals in code of uC).

The AD621 i just put up as a reference. I am open to IA suggestions. I am not fixed at this. My reason for only mentioning AD621 was that in a comparison with a few other IAs, it stands out. For reference, here is a list of those IAs :

INA118U
INA131AP
INA141UA
INA333AIDGKR
AD620ANZ
AD621ARZ
AD623ARZ
AD627ARZ
LT1167CS8#PBF
LT1920CN8#PBF
LT1789CS8-1#PBF
LT1168CS8#PBF
LT1101CN8#PBF
LT1102CN8#PBF


Initially when i posted this thread, my idea was to have a summing amp module, AND a separate control module.

The replies point me to an all-in-one compact system, ofcourse with reasons. I am still ready to go this way. However, this contradicts my original idea to make a modular system in which if one part fails, the whole system does not have to be replaced.

I need to know if this is at all possible. If not, then yes the suggestions are very valuable and i would have no problems re-calculating everything for a compact system.


Thanks