ELAU has claimed a significant feature enhancement to its PacDrive automation systems, without compromising stable servo feedback loops for fast commission
Radio frequency identification (RFID) is a contactless identification method that doesn’t require direct line of sight. The "ID" comes in the form of a portable database on a coded tag that can store manufacturing process data or identification numbers. Barcode technology, for example, requires line of sight, as well as some direction orientation.The "tag" in an RFID system has a memory that can be read-only, write-once-read-many (WORM), read-or-write, or a combination of all three. The tag can store information about the item to which it is attached. It may store information about processes that must be performed. With read/write capability, process data can also be written to the tag.TagsTags are available in a variety of memory types and data capacities. Permanent, read-only memory generally has a serial number programmed when the tag is manufactured. It has an unlimited life. Random access memory (RAM) requires a battery to maintain its data. Data capacity of RAM varies from 2 K bytes to 32K bytes or more. Many electronically erasable programmable read only memory (EEPROM) tags have specifications for limited write cycles of about 100,000, although they can often be written reliably to more than 500,000 cycles. Read cycles are unlimited. Data capacity of EEPROM memory varies from a few hundred bytes to several hundred, while the data has a life of 10 years or more.Recently developed ferroelectrical random access memory (FRAM) is gaining popularity among factory automation applications. Without a battery, FRAM has the virtually unlimited write cycles of RAM.RFID has two basic tag types. Active tags use a battery for power to transfer data to and from the reader. These tags generally have RAM memories. Active tag advantages include longer transmission distances between the tag and the reader. Disadvantages include battery maintenance.Passive tags use the RF field of the reader for power. These tags can have any of the four memory types. Advantages of passive tags include longer service life because no battery is required for data transmission. In the case of RAM memory, batteries are used only for data storage. Batteries in passive tags, depending on the amount of data transferred and number of times, can last for many years. One disadvantage is slower overall tag read or write times, as there is a startup time when the tag enters the RF field of the reader.Readers The other end of the RFID equation, reader heads come in a wide variety of shapes and sizes. Distances between tags and readers vary from a few millimeters to several meters. The data transmission frequency and the size of the reader and tag determine the distance. Frequencies used in most RFID applications vary from 125 KHz to 2.45 GHz. Higher frequencies, in the MHz and GHz range, enable longer transmission distances. Readers and tags are normally sized proportionally to one another. In general, a smaller tag will require a proportionally smaller reader, and will have a shorter read distance between the two. Reader sizes vary from a 10-mm diameter cylindrical barrel type to units built like metal detectors that you could walk through.Main RFID Selection Criteria - Distance between tag and reader- Tag speed at read- Amount of data- Type of machine control- Size and shape of reader head and tag- Type of data- Whether read only or need to write to tag- Data life span on tag- Number of anticipated read/writes
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