See SG1 for newest architecture.
The G5 module is an intelligent four-channel module utilizing four A/Ds and the motherboard resources processor/FPGA. The G5 module is designed to read output signals, and supply excitation voltages that are commonly used in applications with pressure transducers, weigh scales, and strain gages. Each channel incorporates an Σ-Δ modulator, a PGA, and on-chip digital filtering intended for the measurement of wide dynamic range signals. Each channel contains a fourth order digital filter, with several programmable filter options. When properly applied the filter has deep notches at either 50 or 60 Hz.
The G5 may be utilized with AC or DC excited load cells. When using AC excitation, the G5 module switches the polarity of the excitation voltage from cycle to cycle. When utilizing AC excitation, consecutive A/D samples are averaged using different reference voltage polarity removing any system wide DC offsets.
The ‘on-board’ processor removes the user from the details of managing the A/D communication, register access and sample timing. The processor firmware provides the user with a simpler user interface with high-level commands and post calibration data. The module also contains internal factory calibration values, stored in Flash. The G5 automatically recalibrates for changes in reference voltage and die temperature.
Both internal and system calibration are included on chip; thus, the user has the option of removing offset/gain errors internal to the A/Ds only, or removing the offset/gain errors of the complete end system.