What are the advantages and disadvantages of having a sensor internal amplifier on a load cell?

Systems without internal amplification must receive supply voltage from an external source and must send small signals (i.e., 30 mV) back to the amplifying source.

A good sensor output may become distorted by the electrical noise. These errors can be large and give signal-to-noise ratios of less than 20.

Internal amplification is a good way of reducing the effects of noise. The internal amplifiers are housed in the same unit as the sensor. This ensures the signal amplification is accomplished inside the transducer. This also makes the system less vulnerable to electrical noise and creates a higher signal to noise ratio.

The larger output allows A/D converters to create a higher-resolution output. Because the internal amplifiers are so close to the sensor, line drops in excitation are eliminated.

The amplifier outputs are low impedance, and internal amplifiers, although they have some ripple associated with them, they don’t contribute noticeably to system inaccuracy and signal-to-noise ratios of 10,000 are not uncommon. Internal amplifiers may not be feasible under certain conditions. Specifically, the circuitry in the amp cannot be subjected to extreme temperatures. If sensor is placed in a location inaccessible to users (hazardous environment, small space, long distance), zero and span adjustments may not be able to be tweaked when needed. Internal amplifiers increase the overall size of the unit, which may be concern in some applications.