Many industrial automation and process control solutions require precision sensing of multiple process or control variables. Such variables include temperature, load, force, light intensity, motion, position and voltage. TI’s newest family of embedded microcontrollers (MCUs), the MSP430i20xx series, provides for up to 4 integrated 24-bit sigma-delta analog-to-digital converters (ADC) with low per channel power conversion. The sensor output can be sensed directly via a differential input programmable gain amplifier (PGA) prior to the 24-bit ADC. The PGA provides for a high impedance buffer with unity gain or a software-defined gain of up to 16. In line-powered solutions, used commonly in industrial applications, the multi-channel ADC solution provides for simultaneous monitoring of multiple sensors without exceeding system current thresholds defined by the communication loop. It also enables extended battery life in multi-channel battery-powered sensing applications. This paper will review line-powered solutions configured as a 2-wire transmitter, where the communication loop provides power to the system and as a 3-wire and 4-wire transmitter, where power to the system is independent to the communication loop. The MSP430i20xx family of MCUs provides support for these configurations up to operating free-air temperatures of 105 degrees Celsius.
