Use RFID to improve your automation systems

Senior Technical Editor Dan Hebert, PE, addresses RFID technology and explains how RFID systems are being lnked to process automation systems to deliver process improvements.

By Dan Hebert, Senior Technical Editor, PE

RFID TAGGING is all the rage thanks to supplier mandates from Wal-Mart and the Department of Defense. Most RFID systems are simply implemented at the back end of processes directly before shipment and have no effect on process automation systems.

But there is an alternate path to RFID that satisfies customer demands while providing an avenue for process improvement and return on investment. This path uses RFID early and often in the process to produce quantifiable process improvement.

RFID improves process automation systems by allowing items to be tagged and traced throughout the manufacturing process. This tag and trace information can be used to reduce inventory, improve quality, and automate manual process.

Bar codes can be used to track and trace, but RFID is a better technology. “RFID tags can be read in bulk at distances up to 30 feet, do not require line of sight, can store large amounts of information, and are re-writable,” reports Rashesh Mody, chief technology officer at Wonderware.

Wells’ Dairy in LeMars, Iowa, and Rockwell Automation teamed up to implement an RFID system at the country’s largest family-owned dairy company. “From the outset, we viewed RFID as a catalyst for making process changes that improve business performance,” says Brad Galles, process controls manager, Wells’ Dairy. Improvements included:

Automation of manual processes: As RFID tags are applied in production, a time and date code is entered into a database for every product’s serial number. With this information, Wells’ Dairy can automatically develop pallet tags instead of manually keying in information.

Increased safety and quality control: Prior to RFID, plant personnel had to hold entire pallets if problems were suspected. To err on the side of safety, longer time frames were often used and more product than necessary was placed on hold. With RFID, Wells’ Dairy knows precisely what groups of products are affected during the time of a hold order. This minimizes hold orders and rework.

Increased productivity: The old process of inducting pallets into the automated storage/retrieval system (ASRS) at Wells’ Dairy relied on freezer personnel to precisely place pallet tags so that scanners could read the tag when the pallet was inducted into the ASRS. With RFID, Wells’ Dairy can read the pallet tag as long as it is on the correct side, regardless of its exact location, greatly increasing the efficiency of the ASRS.

Improved shipping accuracy: Because of human error, the ASRS occasionally brought the wrong pallet to the outbound spur. It was the responsibility of the truck loaders to double-check the pallet tag and count cases. When this step was missed, the wrong product was sent to a customer. With RFID tags and readers in the ASRS, Wells’ Dairy can read the pallet tag as it comes out of the ASRS and automatically know if the pallet and count are correct.

Improved insight into inventory: Currently, the production and freezer counts at Wells’ Dairy often show differences due to numerous variables. RFID technology can help with such discrepancies, because each sleeve will have an individual serial number on it. This technology allows the counting of units to be accurate as they pass to and from the freezer, since only sleeves with an accurate serial number will be counted. The others will be diverted and not counted, and duplicates will be recorded and dismissed.

Although concrete benefits can be realized with proper RFID implementation, there are many possible pitfalls along the way. “There is very little information on RFID implementations that has been proven in actual process plants, so the only way to get good, accurate information is through test in your own facility. As a result, we learned a lot about the technology’s capabilities and drawbacks through trial and error,” confirms Galles.

Many RFID implementation problems don’t involve integration with process automation systems, but instead occur at the more basic level of tagging and reading. “Our customers have had problems with tag placement, reader location, reading the right tags at the right time, and printing correct tags,” according to Gregg Le Blanc, technical strategist at OSIsoft.

Because RFID is a new technology, many recommend initial small scale implementations. “RFID solutions offer a challenge regarding upfront determination of ROI, so many companies implement a pilot project to prove the value of an RFID solution prior to wide-scale implementation,” says John Leppiaho, the senior Manager for Proficy software at GE Fanuc Automation.

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