Fieldbus products are industrial automation products used in industrial network communications on factory floors. They link programmable logic controllers (PLC) to devices such as sensors, switches, actuators, motors, controllers, contactors, and transducers. Fieldbus is a generic term for a digital communications architecture designed to replace the 4 - 20 mA analog standard. Fieldbus products require less wiring than conventional bus networks and offer improved reliability and reduced cost. The International Electrotechnical Commission (IEC), the Instrument Society of America (ISA), and other standards organizations have defined physical, data link, application, and user layers for fieldbus products. IEC/ISA SP50 is just one of the standards supported by the Fieldbus Foundation (FF), a non-profit group of suppliers and end-users who are dedicated to developing fieldbus digital communications.