RFID (Radio Frequency Identification)
Product and service tracking and/or counting is a vital part of every business. Supply chain management is rapidly evolving on a number of levels that are vital in today's dynamic and demanding business environment. Part level, product level, case level and pallet level tracking, tracing, security and anti-counterfeiting measures are taking centre stage as a result of cutting edge technological advances in RFID (Radio Frequency Identification).
Imagine the following scenarios:
• A large manufacturing company has many moulds that get pulled out of storage and used periodically over a period of time, whenever a product line gets low. Challenge is that they are high temperature moulds and can only used 15 times before being discarded.
• You have a huge warehouse of different sized saline bags that MUST have validation of being sterilized before being stored back in place prior to being shipped
• Your production line consists of high-unit-value products moving through a tough assembly where the product is cleaned, bathed, painted and baked. e.g a process such as agricultural or automobile equipment production
• A large meat processing plant needs to identify and track product from source thru the various stages of processing.
• The pattern used in manufacturing effects the raw materials selected. Electronic recognition enables 100% accuracy.
• A casting operation has RF Tags attached to wire baskets which travel through a variety of degreasing, etching and cleaning tanks by means of an overhead conveyor - not a job for optical or magnetic identification media.
• RF Tags are used for tool management. Miniature tags can be placed within tool heads of various types such as block or Cat V-flange, or even within items such as drill bits where individual bits can be read and selected by reader guided robot arms.
• Tags are used as station readers at the ends of warehouse aisles to monitor lift truck activity. High throughput rates permit multiplexing via multiple antennae per reader.
The diversification of consumer needs has made RFID systems an important means within the 
manufacturing industry to achieve more efficiently multi-product production. Supply chain management in particular, from manufacture through to final point of sale, has become a major logistical tool. Consequently the most common applications in manufacturing are tracking goods in the supply chain and, tracking parts moving to a manufacturing production line. The results are further reductions in personnel expenses and work time, increased productivity, and reduced stock volumes.
The RF Tags can be simultaneously accessed by read write antennas and, unlike bar code systems; RFID systems do not require a direct line-of-sight between the antenna and tag. In addition they are able to stand extreme temperatures which further extend their application in a manufacturing environment, enabling them to fulfill multiple functions. Typically a RFID system consists of 1) the RFID tag or portable memory, 2) the transceiver (sender/receiver) antenna and 3) the system controller to interface with the "real" world and verify the data transfer.
Within the RFID tag process, control functions are stored and up dated as the product progresses through out the operation. Specific uses of the data within the tag for process control include part routing, program operations, bill of material, build orders, component needs and specific operations which may by unique to only a few products. While operating in a process control function, the RFID tag can also be used as a portable data base providing station to station data transfers, repair information, operation status, operation values, pass/fail data, host data transfers, part history and raw SPC data. One of the major advantages of using an RFID system in manufacturing is a major reduction in the size and complexity of the PC or PLC program reducing the cost associated with programming and also reduces the scan time of the controller.
Radio frequency identification systems are providing the means in manufacturing to decrease product failures by controlling the process quality of products while allowing the manufacturer to better utilize the resources at their disposal. Flexible manufacturing requires timely information provided to each location performing an operation. RFID can provide this information in a most economical way. As knowledge is gained through experience in using RFID, the applications will become more wide spread and common place. This will also have the effect of reducing the cost of an already very economical system. RFID in manufacturing is growing with each successful application and to continue this growth towards better ways to produce better products, it is increasingly important for the end users to become more knowledgeable about the uses and applications of RFID.
Read / Write or Read Only?
RFID systems have been developed that can be used much like bar code, as an identifier for a "look up" table, which are known as READ only. As the name implies, the RFID tag contains a code that can only be read and is a unique identifier. This identifier becomes the "license plate" associated with the specific person, place or thing with the specific information concerning the identified item stored in a remote location such as a computer or PLC. Typically the code on a read only tag is "fixed" and may be referred to as fixed code, even if the RFID tag's code can be altered by mechanical means. The code of a read only tag may be as simple as a binary number or as complicated as an altered echo of a sent frequency which is associated with a predefined source code. Read only systems are used when a central host (computer) contains and controls the information associated with the person, place or thing being identified.
Read/write RFID systems provides for data transfer and storage without contact and may be used with or without a central controller. Data associated with the person, place or thing can be stored in the read/write memory and altered as needed, without physical contact between the tags and transceiver (antenna). Read/write tags have memory sizes of 8 kilo bytes or more and thus can be used as portable data bases saving memory allocation and network data transfer time. Read/write tags can be used as bill of materials for transport, or process data, smart credit cards, quality control data (pass/fail), in process repair data, personnel security data and many other uses.
Active or Passive?
RFID systems can be either ACTIVE or PASSIVE. An active RFID system uses a power source (battery) contained in or on the remote tag to send and/or receive the data which is contained in the tag.
A passive RFID tag does not use any power on the tag to send or receive data. A battery may be present on a passive tag to retain memory but is still considered passive if the battery is not used to send or receive data. A passive tag may receive its power to operate by electromagnetic flux transfer, frequency reflection or absorption, or other technology.
Some Passive tags (those with static RAM memory) have an infinite life; no matter how many times the tag is read or written to. Passive tags with EPROM memories can be read an infinite number of times, but have a limit to the number of times they can be written to, some as high as 1,000,000 times per byte. The passive tag's power to communicate is received from an external and remote source. For this reason whenever the specific application calls for the tag to be read or written to, many times a day or frequent and long data transmissions or for infinite data storage, passive tags should be selected. Successful applications of passive tags include most manufacturing operations where tags are in use every few seconds and throughout multiple shift operations such as engine assembly, car assembly, heavy machining operations, component manufacturing, as well as most applications that an active tag can do.
An active tag has a limit to the amount of time it can be used before its power supply needs to be replaced, if it is replaceable, or, if not, disposed of. Therefore, active tags are most often utilized when there is a limited amount of data to pass and/or the tag is in limited use (read or written to only a few times a day). Some active RFID tags begin to lose range as their batteries begin to fail.
When active tags are read or written to for only a few seconds a day their effective life can be measured in years, while if they are used for an hour or two a day, their effective life can be measured in weeks or days. Active tags have an advantage over passive tags in that they can be read or written to at a greater distance from the transceiver (antenna) and initially might transfer small amounts of data faster than passive tags. Many active tags use static RAM memory for data storage and use the battery to also back up the memory. If the battery fails, the data in memory is lost. Active tags can be successfully applied to personnel ID, car toll applications, rail car ID and bill of material, light rail ID and routing, smart bank cards, warehousing bay/ location ID, and many other applications.
Machinery Automation & Robotics
1/101 Derby Street
Silverwater NSW 2128
Phone: (61) 2 9748 7001
http://www.machineryautomation.com.au