Is RFID ready for the plant floor?
The latest in wireless identification technology offers potential for using radio frequency identification (RFID) on the plant floor for asset maintenance.
Most people use RFID technology on a daily basis without even realizing it. Have you ever used an electronic device in your car to automatically pay tolls? Do you use an access card or fob to gain employee entrance to your workplace? These examples are common uses of RFID technology.
How RFID works
RFID tags work by emitting electronic signals — either actively with its transmitter, or passively by waiting for a signal from an RFID reader before reflecting back a response signal (Fig. 1). For the purpose of this discussion, the focus is on passive tags, which are significantly more affordable and more likely to be used in a plant environment.
Passive RFID tags can be read-only or read/write tags, allowing information to be updated with RFID readers that can be attached to standard mobile devices. Currently, the storage space on passive, read/write tags is approximately 2 kB, enabling only small amounts of information to be stored. But look for this number to grow as the technology advances.
RFID tags are available in a wide range of signal frequencies. Low-frequency tags typically operate between 30 and 300 kHz. On the other end of the spectrum, ultra-high frequency (UHF) tags operate anywhere from 300 MHz to 3 GHz, sending information faster and farther than lower frequency tags. Because they use more power, the higher frequency tags cost more, and are subject to limitations in transmitting signals when attached to objects containing water or metal. The distance most passive tags can be read from varies according to the frequency, ranging anywhere from a foot or less for low-frequency tags to 3 ft for high-frequency tags and 10%%MDASSML%%20 ft for UHF tags.
The higher frequency signals operate over longer distances. However, the higher frequency signals cannot penetrate through different substances as easily and therefore require line of sight (or at least a better line of sight). Therefore, the higher frequency readers have more problems reading tags where obstructions exist.
RFID facts and myths
RFID technology continues to evolve at a rapid pace. Spurred by the recent push from Wal-Mart and the Department of Defense (DoD) requiring manufacturers to standardize, a new market for RFID integrators has emerged and is stimulating its advancement and acceptance into the mainstream. As the technology grows and the costs of RFID implementations begin to decrease, greater opportunities for this emerging technology are being considered.
New trends in technology can sometimes be compared to an urban myth — it makes a great story, but in reality, is full of a lot of hype, mixed with little truth. RFID is often spoken of in the context of product tracking from production to distribution — the ability to identify a product, where it has come from and where it’s going in the supply chain, as well as multiple traits about that product.
In reality, RFID tags for most products — as defined by standards being supported by Wal-Mart — would hold a 96-bit electronic product code, which is essentially a unique numeric code identifying the item, manufacturer, class of product, and serial number. But RFID has the potential to be much more than an electronic identification system for products moving throughout the supply chain — especially on the plant floor.
How the use of RFID and bar codes differ
The variety of tags and communications frequencies used by RFID is one of the technology’s key advantages, offering plants the ability to vary the type of tag depending on the application. An additional benefit of RFID that other automatic ID technologies, such as bar codes, lack is the ability to read a tag without requiring line of sight (depending on the RFID frequency range). This feature is of particular use in industrial or dirty plant floor environments where dust, grease, or severe conditions could render bar codes unreadable.
RFID will not necessarily replace bar codes, but will likely be used in tandem depending on the environment. RFID tags can be protected from various elements by enclosing them in plastic casings, because only the signal needs to be received, rather than the visual requirement of bar codes. RFID tags can be welded or mounted onto an object, often at a distance from the ground. In addition, combining RFID tags with sensors introduces the possibility of capturing and transmitting temperature, vibration, or other important equipment readings. This combination is the beginning of a new practice that will offer tremendous benefits to plant floor data collection for years to come.
RFID on the plant floor
Industrial plants can benefit from these recent advancements in RFID, especially in maintenance and engineering functions. RFID is moving beyond merely an automatic identification technology to play a key role in holding information of value to workers at the point of performance. Information that can be stored on RFID tags includes:
Preventive maintenance schedules
Previous work orders (quantity varies according to tag memory)
Last several readings (quantity varies according to tag memory)
Critical spare parts lists.
Plant engineers are beginning to identify opportunities for RFID by considering areas where timely and accurate data collection and access to readings are important. Asset maintenance is one function in particular that can benefit from using RFID to access and update important information.
Potential RFID implementation areas within the plant are those that present challenges in maintaining bar code integrity, or areas where wireless coverage is unreliable. For example, some remote production facilities may house critical assets, but do not support the possibility of installing wireless local area networks, preventing technicians from retrieving real-time information. Instead, RFID tags could be used to store the last official reading taken at a piece of equipment, or last failure code for a break/fix job performed, allowing technicians or engineers at the point of performance to make more knowledgeable decisions.
RFID presents the opportunity for workers to gain access to critical information that otherwise would not be available. For example, a meter may have values that can be captured on the RFID tag, and then accessed by an engineer who will make parameter adjustments on the meter. In addition, on some of the tags that offer more storage capability, information such as the 10 previous readings could be stored on the tag and enable mechanics to perform automatic trending on the spot for better troubleshooting. Technicians performing break/fix work could benefit from an RFID tag holding the preventive maintenance schedule or tasks, allowing them to perform PMs while the critical asset is already offline.
As RFID technology matures and costs decrease, cutting-edge companies that have invested heavily in enterprise asset management (EAM) and want to gain more out of their investment are pairing RFID with mobile software, which allows work orders to be updated with key data points that are transferred to the RFID tag. This information is routed back to the EAM to make reporting more meaningful, maintenance more effective, and reliability planning more efficient.
As with all new technology applications, there are certain risks involved in making the move to RFID. One of the biggest risks is the cost of the technology. Passive tags, which would be most appropriate for tagging assets on the plant floor, range in price from $0.10 to $0.50 per tag, depending on the operating frequency. Compared to the cost of bar codes, this represents an increase of 10%%MDASSML%%50 times the cost for tags alone.
Because RFID emits radio signals, certain liquids or metals can interfere with the transmission. However, depending on the system design and engineering of the tags, this shortcoming can be overcome. For example, low-frequency tags tend to work better on metal items, and are being used successfully. But you should be aware of this limitation when considering an RFID implementation.
On the horizon
For the right opportunities, RFID can provide enriched data in environments where limited access to wireless coverage often impedes a worker’s ability to access important information at the point of performance. Within asset maintenance in particular, companies can expect to save considerable effort and time by giving engineers and technicians the ability to view failure codes or recent readings, when previous methods (such as paper-based data entry) would hinder a technician from knowing if work was performed on a piece of equipment in the prior shift or the most recent rounds taken.
While many consider the technology to be immature, RFID has actually been in use since the 1970s. Only recently has it gained widespread attention because of the Wal-Mart and DoD requirements to use the technology to better track and identify products. As more technology providers and systems integrators jump on the RFID bandwagon, the costs and risks involved in RFID will be considerably lower.
Author Information Richard Padula is the president, CEO, and founder of Syclo, a mobile computing software provider for the enterprise. He has been developing large-scale enterprise applications for more than 15 yr. He can be reached by phone at 800-567-9256, or by email at email@example.com .