My first internship experience at Texas Instruments was in applications engineering. The project I worked on was to create an analog front-end for a programmable logic controller (PLC). This project was the first part of a larger project to create a PLC reference design. The goal was to crete a functional, highly accurate PLC analog front-end that could then be adapted for use in the final reference design. This stage of the project proves the analog frint-end is accurate before complicating the system with switches to make the inputs universal and digital control circuitry.
The PLC front-end consists of 6 inputs: Universal current, universal voltage, 2 types of thermistor inputs, RTD input and a thermocouple input. The system was controlled using a microcontroller on a USB-SM-DIG, a small control board used with some of Texas Instrument’s EVMs. The project was successful with the analog front-ends measuring with very high accuracy. Please see the design review and final presentation below.
PLC Analog Front-End Board
PLC Analog Front-end Channels