A common request from many engineers I talk to is the need for a “faster” RFID read/write system. Usually, this is due to the fact they are increasing their overall line speed and decreasing the amount of time that a work in process item dwells in one station. This is a good thing. We all want to make more widgets faster. However, in addition to increasing the number of widgets that come off the production line and the rate at which they come off, the demand for quality has increased significantly. This is also a good thing. This certainly leads to a win-win between the manufacturer and the consumer. As the demand for quality increases so does the amount of data. Statistical process control, lineage data, build data, etc. are represented by large amounts of data. So the tag has to have enough memory and the reader has to have enough speed to keep up with the process. The amount of data transferred over a period of time is called throughput.
In RFID readers/writers, throughput is usually represented as bytes or kilobytes of data per second or milliseconds. The read/write speeds of all RFID systems are related to the amount of data being read or written to the tag. So, if high throughput is a requirement, a feature to look for in the reader/writer is the buffer size. I don’t want to get too deep into the technical weeds of data transfer, bit rates, baud rates, etc. so I will explain it from a marketing guy’s perspective. Think of an RFID system as a data delivery system. In this delivery system an imaginary tractor-trailer is what delivers the data from the reader to the tag and the tag to the reader. The trailer represents the aforementioned buffer. The trailer or buffer can hold a specified amount of data, 32Bytes, 64Bytes and so on. This is determined by the manufacturer of the system. Therefore, there may be two systems that operate at the same speed, but have a totally different throughput. Back to the tractor-trailer example, there can be two semi’s going down the road at the same speed but one has a trailer that is half the size of the other and can only carry half as much product(data in this case). So in order to transfer the same amount of data, the half-size trailer has to make two trips (cycles) whereas the larger trailer makes only one. In a case where the amount of data that needs to be transferred is multiple thousands of bytes or kilobytes, that buffer size becomes more important because the more cycles or trips that have to be completed the slower the transfer.
Ultimately, speed is a relative term in the world of moving data from one point to another. In order to future-proof your production line, look a little deeper into the features of the system to make sure you’re investing in technology that is not only fast, but fast and moves a lot of data.
There has been a lot of talk in the industrial automation about RFID. In past blog posts we’ve discussed topics like RFID ROI and when to use IO-Link RFID. We could talk about things to consider when implementing RFID into your plant or different applications for days. In this entry, though, I’d like to get back to the basics a little bit.
Area of Application for a Passive RFID System:
RFID is used to accurately identify an object on which the tag is placed. In addition to identification, bject-specific information, like maintenance data is contained on the tag.
How It Works:
Since passive RFID tags contain no battery, the tag is powered up or “woke up” by the RF waves emitted from antenna of the same frequency. Once a tag is located in range it is powered up by the antenna and its memory can be read and transmitted to the processor. The time it takes the reader to extract information from the tag is usually measured in milliseconds.
Three Main Components of a Passive RFID System:
Tag – A combination of a chip and internal coil. The chip is where the data is held in the memory and can contain a few bytes of data or thousands of bytes of data depending on the capacity of the chip.
Antenna – Connected to the processor by an external cable or sometimes contained inside the same housing, the antenna transmits the data to and from the tag back through the processor
Processor – The role of the processor is to organize the data as it is being read or written. The processor is usually connected to a controller, like a PC or PLC, and performs the task issued by the controller.
“The world is full of magic things, patiently waiting for our senses to grow sharper.” -W.B. Yeats
At some point in everyone’s life, they find themself at a proverbial crossroads. They are forced to make a choice that will impact the future. These decisions could create personal fulfillment, affect the people around them, and influence their role in an organization. OK, maybe that’s a little strong for the blogosphere, but what I am trying to say is there is a crossroads where one must differentiate the benefits of a product when the companies that sell them all claim their product is the best and will definitely meet or exceed the needs of their customers.
These days, decision makers not only put their job on the line, but also the future of their company when they pull the trigger on buying new equipment. And, let’s face it, those wacky marketing people (I can say that because I am one) haven’t made it any easier to discern one product from another. Let’s use a UHF RFID system, for example. One could pull spec sheets on 10 different controllers and conclude that “they’re all the same”. I have heard that exact phrase spoken multiple times from customers who were considering the purchase of a system. However, we all know that is very far from the truth.
As marketing folk, we have a great challenge in front of us in that we must try to make our product appeal to the whole market in which we are selling. Most of us fell into a monkey-see monkey-do mentality and our spec sheets are filled with speeds and feeds so we can compete with the next guy’s product. So, how is it possible that our customers can make an educated decision when everything appears the same? We listened to the market, and we wised up. Instead of just speeds and feeds we added words to help better describe our product. We added words like: “rugged”, “flexible”, “industrial strength”, “turn-key”, .etc. Now most spec sheets and product descriptions include speeds, feeds, AND fancy buzz words.