Force measurement interfacing transducer direct to microprocessor

The MSP430Fxxx series of processors from TI has long been a favorite of mine, it evolving from the 4 bit TSS400 family I used to create a thermocouple radio sensor some 20 years ago. The characteristics of this 16 bit processor and its unique set of peripherals create a very high performance, low chip count transducer module. Apart from its low power architecture and high density memory allowing high level language programming. It has a really great 16bit  (or 24bit if you reduce the filtering) sigma delta converter, this unit along with its programmable gain amplifier means that very low level sensors (thermocouples, strain gauges) can be connected directly. There are also derivatives aimed at energy monitoring with up to 7 analogue channels and on-board maths module.

Using the internal 1.2V reference provides a full scale input range of +/- 0.6V when the gain is set to 1, or +/- 18.75mV when the gain is 32. The resolution of the 16bit converter is then 0.286uV, more than sufficient for thermocouples and 2mV/V bridge sensors. The application report SLAA220 for a single chip weigh scale covers the MSP430F42x in more detail.

5KN Load Cell attached to Test Stand

Load Cell 2mv/V 5KN FS

Leave a Comment