Ethernet and friends. Basic TCP/IP and other Ethernet varieties such as EtherNet/IP, EtherCAT and Profinet have replaced complex, point-to-point hardwiring and some fieldbuses on many machines and production lines. The resulting savings and simplicity allow many devices to connect in more different ways that weren't possible or affordable before.
MTConnect is a four-year-old, factory-floor communication protocol that's universal, extensible, royalty-free and founded on web-based HTTP and XML programming. The MTConnect Institute says it's the first standard to define a common dictionary for manufacturing data and machines. This means names, units, values and context data don't have to be repeated for each application, which saves setup time, labor and expenses. Compliant devices process information once at the local interface or machine tool, and then provide that data in a consistent format to any application, such as ERP, MES, production management systems, maintenance systems, browsers and spreadsheets, which enables a plug-and-play atmosphere that mimics PCs and the IT realm. Also, MTConnect is the foundation for ShopViz, which is a web- and cloud-based system that allows 24/7 monitoring of one or more machines.
PackML stands for Packaging Machine Language, and defines a common approach or machine language for automated equipment. It's administered by the Organization for Machine Automation and Control, and its main goals are to encourage a common look and feel across packaging and related machines, production lines and plant floors, and to enable and encourage industry innovation. In addition, PackML was adopted as part of the ISA88 standard in August 2008. And PackML has been implemented by users and machine builders using a variety of control platforms.
Fieldbuses such as DeviceNet, ControlNet, Profibus, AS-I, CANopen and others are used in many machines and production lines, but just as they replaced hardwired networks, they're being replaced by their Ethernet-based counterparts.
IO-Link is a device-level networking system that consists of IO-Link devices, generally sensors, actuators or a combination, a standard three-conductor sensor/actuator cable, and an IO-Link master device that can have one or more ports. Only one IO-Link device can be connected to one port, which makes IO-Link a point-to-point system and not a fieldbus.
Wireless and mesh-enabled protocols, such as Wi-Fi, ZigBee, Bluetooth and others, have joined traditional radios and cellular telephone technologies on many machines and production lines. Choice of method is typically determined by distance, communication speed, ambient interference and other issues.
This article is part of our November 2012 cover story "Connect Your Islands of Automation."