A small-scale industrial communications network using a power line modem

Industry relies heavily on instrumentation to provide information on process conditions. The analog information that is produced by this instrumentation is typically transmitted to a central location for monitoring and to make adjustments to process controls. Current industry practice is to provide a hard-wired path from each instrument to the monitoring location. This thesis provides an alternative method of transmitting process information, by developing a network that will allow multiple instruments to communicate over a single cable. This thesis provides a means of reducing installation costs dramatically. The network developed is based upon power line modem technology. A power line modem allows data to be passed across a medium which also provides alternating-current power. Additional benefits are gained by allowing the industrial communications network to provide power to field instruments.;A network client prototype was developed and tested. The prototype had the ability to accept an analog signal for transmission over the network as well as generate an analog output from data received from the network. Two prototypes were built and tested. Data transmission was extremely reliable with a data error rate near zero.