Low-Cost I/O Modules Reach Out For Analog World

Allowing use of any analog sensor with almost any PLC model, even a PLC without analog input capability, MSP family of analog-to-pulse I/O modules provides one analog input or one analog output interface between the PLC and the analog world. Communications between the MSP and the PLC is over proprietary single wire communications. MSP input modules convert the analog input into a 16-bit digital word that is transmitted serially one bit at a time to the PLC's discrete I/O point. The analog output level from an MSP output module is set when the unit receives a digital word, transmitted to it from the PLC. Modules are available for thermocouple, RTD, current, voltage, potentiometer, and frequency inputs, and voltage or current outputs.