Monorail systems are common material handling solutions. Most applications for monorail systems involve automotive assembly processes where anything from doors, to engine blocks, to entire car bodies is transported from station to station. This begs the question, "How does the monorail control system know when it has reached the target station?" Fortunately, this is a rather simple task using a modern, industrial RFID system. The steps to implement such a system –where each monorail carrier controls itself using an onboard monorail controller -- are as follows:
- An industrially hardened RFID tag is attached at the location that indicates the assembly station. This tag is used to store data that the onboard controller can use to identify a certain assembly step. Some users put descriptive information like “Door_Line_1” on the tag while others apply a number. Others don't write any data at all to the tag, but rather utilize the unique “license plate” code that is part of the tag.
- A read head and control interface is mounted on the monorail carrier. The read head interacts with the tag, retrieves the station information, and sends it on to the control interface. The control interface communicates with the onboard monorail controller using one of the many open protocol standards offered; EtherNet/IP and PROFIBUS come to mind. Even RS232 is used on occasion.
- Now that the controller receives this location data, it knows where it is along the track. This information enables the monorail to make adjustments, for instance, raising or lowering the item it is carrying, as needed. The industrial RFID systems become the eyes of the monorail system.