RFID (radio frequency identification) enables data to be read and captured wirelessly using radio waves. This can then offer you a much more versatile solution as the tags do not require direct line-of-sight with the scanner in order to function, and this form of auto-ID technology allows for fast, cost-effective item locating and tracking. However, it does require more infrastructure than bar codes.
Without requiring direct line-of-sight now makes performing an asset audit or an inventory audit much simpler and far less time consuming. An operator will only have to sweep the warehouse or room (proximity depends on what type of tag is fitted) in order to perform the audit and capture the tags. The scanner will even read tags which are hidden from view, such as items on a pallet or asset register items under a desk. These tags are also not susceptible to defacing or surface scarring as they will still work, and can be read when covered in grease and dirt etc.
‘Passive’ tags have a small transponder and antennae in the inlay and can also be pre-printed with a conventional bar code too, either LF (low frequency), HF (high frequency) or UHF (ultra high frequency) depending on the requirement. The energy received from the radio waves activates the transponder in the tag, and this transponder then sends a signal back to the scanner or reader with its own unique ID and any information stored on the microchip.
The tag can be written at any time and can also collect, send and store information when read for later analysis. The typical read range for these tags are 3 metres, but you can have larger passive tags that can be read from further away as they have a bigger antennae built into the inlay. The price per tag is more expensive than the bar code and ranges vary in terms of the tag size and usage application.
‘Active’ tags are RFID tags that are fitted with a battery. They operate in much the same way as passive tags but unlike the passive tags they do not require a signal from the scanner to power up as they continually emit a signal. The signal repetition can be pre-programmed in order to preserve the battery life and according to particular requirements, so in some cases it will be better for the signal to be emitted every minute rather than every 10 seconds.
They can come in different shapes and sizes depending on the exact nature of the requirement, and supplied to differing specifications to allow for steam cleaning, freezer and oven temperatures etc. Where tags need to be fitted to moving assets such as manufacturing tools, they can be ‘podded’ which is where they are encapsulated in an outer plastic cover to protect the transponder and antennae from any movement and impact damage.
Read ranges for active tags greatly increase and can be read from distances as far away as 100 metres. They again understandably require no line-of-sight but the cost per tag increases and they only have a life as long as the battery lasts. Frequent signal emissions will provide a battery life of around 5 years whereas more measured emissions can provide a battery life of over 10 years.