Problem: Bar code labels or photoelectric mechanical flag seals are attached to the pallets of hanger conveyors that are used to transport small lots of CRTs or monitors for TVs and PCs in the processing and assembly lines. Because the hangers sway, the reading depth changes and the labels or seals sometimes cannot be read, causing the line to stop. The number of models being produced has increased due to diverse user needs and the appearance of LCD and plasma TVs. This has created the need for frequent line changes, and the resulting complex processes make control by a host computer extremely difficult.
Mount a Data Carrier (ID Tag) onto the hanger pallet carrying the product. Write the data to distinguish models in bits (for example, 0000 for product A, 0001 for product B, and 0010 for product C, allowing 16 models to be distinguished with four bits). Install a system with Intelligent Flags and a PLC at each process. When the work at each process ends, write the process end flag data onto the Data Carrier. Use a "1" flag for ending, and a "0" flag for not ending (for example, for four processes, use 0001 for the end of process 1, 0011 for the end of process 2, and 0111 for the end of process 3. These will enable process progress management).
The Intelligent Flag Series can be set up with a smaller investment than that required for mechanical flags for distinguishing models and managing process progress. For example, for distinguishing models only, a single set (V600-HAR92) can handle up to 64,000 models, distinguish 256 models, and control eight processes. The V600-HS67 Sensor can read or write with a pallet sway of up to approximately 100 mm or 3.9 inch. (For more stable communications, it would be better to mount a Data Carrier to the top of the hanger.) High resistance to noise enables stable communications in FA environments. The V600-D23P66N is available at a very reasonable price.
Since there will be no reading errors or missed readings such as those that occur in systems using bar codes or mechanical flags, accurate control will be possible and there will be no more stopping of the production line. This will increase productivity. Unlike mechanical flags, Intelligent Flags have no mechanical parts, allowing you to configure a maintenance-free system. By managing the process progress with process-end flags, the quality of product processing and assembly can be raised (contributing to ISO 9000). There is no need to revise the flags when the number of models increases as is required with mechanical flags, allowing you to configure a highly flexible system.