Beyond The Supply Chain

By David Crump

What's missing? The direct link from the RFID system to the industrial device. There are all kinds of value in establishing this connection.

For example, RFID tags can include data and instructions for a controller, I/O system or some other device to execute. In scenarios such as these, a true M2M connection is established, where machines talk to one another and act independently—without a human interface. For instance, if an RFID tag contains information pertaining to a particular manufacturing or operational process, the RFID interrogate can read the tag and an I/O system can poll the reader, get the information and give the manufacturing or operational equipment it's controlling the appropriate commands.

Here's a for instance: Let's say an RFID tag is attached to an individual part coming down an assembly line. The tag identifies the part, distinguishes it from similar parts and provides specific instructions relating to the next stage of assembly—torque specifications, for example. The RFID reader gets this information from the tag, and an I/O system, PLC or other intelligent device polls the reader. This intelligent device then executes the necessary logic and gives the manufacturing equipment its controlling the appropriate instructions. In our scenario, a robotic screwdriver receives the correct torque settings and applies them to the part.

RFID in the Real World
The Sao Paulo, Brazil-based company Flextronics designs, builds and ships consumer electronic, computing, medical, automotive and other products to a worldwide list of OEM customers. These customers include Motorola, Dell, Microsoft, Xerox and Hewlett-Packard, which often just provide the packaging for products actually built by Flextronics. For example, most assume HP makes and ships its well-known line of printers itself. In reality, all printer components are collected and assembled by Flextronics, then shipped to the warehouses of HP retailers.

This being the case, Flextronics has had to implement RFID in its warehousing and shipping operations. (This, no doubt, is due in part to the mandates of Flextronics OEM customers, who, in turn, have had to respond to the earlier-mentioned RFID requirements of Wal-Mart and other large retailers.) A major difference between Flextronics and many other enterprises, however, is that RFID plays a major role in the company's assembly processes. All printer housings include an RFID tag, manufactured by UPM Raflatac, containing basic information about the printer—product ID, original manufacturing date, and so forth. As the printer moves down Flextronics' assembly lines, the various components (cartridges, paper trays, rollers, etc.) are installed in the printer housing. After each component or procedure is completed, the SAMSys RFID interrogator encodes data to the tag indicating that a component, adjustment or test has taken place.

At four different stages of the assembly process—the last of which is the product's final testing prior to shipping—an RFID reader interrogates the tag and sends the data over Ethernet to an Opto 22 SNAP Ultimate I/O system. The SNAP Ultimate I/O is an intelligent industrial controller that uses sensor interfaces to connect to and communicate with a number of mechanical and electronic controls and systems on Flextronics' printer assembly line. After receiving the tag data indicating a component has been properly installed, or that a line test has been successfully completed, the SNAP system validates the printer by issuing commands to conveyors and other systems that, in turn, send the printer down the assembly line to the next stage. If the tag data received by the SNAP system indicates a part is missing, or a test was failed or never conducted, the SNAP system routes the printer back to start the assembly process over again. If a severe problem exists, SNAP is programmed to reject the printer entirely and send the commands to convey the printer to an area designated for defectives.