Last week I wrote about the number of Industrial Communication Solutions supported by MSP430 microcontrollers (MCUs), the most popular among them being the 4-20 mA current loop. We will be showcasing this solution at the embedded world tradeshow in Germany this week. So what exactly is the 4-20 mA solution?
The current solutions can be either 2-wire current loops that provides the communication channel and power to the field transmitter or the 3-wire current loops that have a separate power line not associated directly with the 4-20mA current loop. In this kind of communication, the resolution is by voltage controlled current source and the total current budget for 2-wire field transmitter is less than 3-3.5mA. This makes the ultra-low-power MCUs extremely suitable for 2-wire communication loop solutions.