Configuring TagNet for a Cabinet Inventory Use Case
Using RFID to maintain Inventory state of items in cabinets is a common use case. This can be for VMI (Vendor Managed Inventory) purposes of consumables or for Assets in storage such as mobile devices being charged. TagNet can be configured to maintain a perpetual inventory of those tagged items when they are added (e.g. replenished or returned), or taken away (e.g. issued).
Note: Ideally you would have gone through a Phase I implementation with Stratum guiding the way and the correct antennas and tags have been chosen and implemented. This is the important starting point so that your use case can be successful and you are not fighting against a bad foundation. This may seem simple but there are many antennas out there such as linear, circular and specialty so refer to the RFID 101 section to ensure you are clear about the terminology and what options are available for passive UHF equipment.
❖When deploying to a metal cabinet, the RF (radio frequency) emitted by the antennas mounted inside will reflect (aka signal bounce) within the enclosure considerably (essentially a microwave effect) dramatically improving readability of even the hardest to read tagged items inside.
❖In most cases the cabinet door has a sensor that is triggered to go off when the door closes. This trigger starts a inventory cycle (aka read cycle) for a reader defined given period of time that is sufficient for the number & concentration of tagged items inside the cabinet. This use case can also be used without a sensor by using a specified dwell cycle to inventory the cabinet (such as every 5 minutes). However there are drawbacks to this approach; because there is no control when the read cycle occurs, someone opening the door in the middle of read cycle could cause some of the assets inside the cabinet to not be scanned, or assets in the immediate area can be picked up with all that RF directed into the general area. In both cases this would show a false positive of asset being removed (or added) from/to the cabinet. Additionally, when placing assets in the cabinet during an inventory cycle could also provide inconsistent results.
❖With the above said, the cabinet inventory will self-correct on the next inventory cycle but the transaction history will still show false positives of assets leaving for a short time. This needs to considered when planning your deployment and setting expectations for the indented users.
❖Mounting the Reader: it is not necessary to mount the reader inside the cabinet storage area itself for a number of reasons: 1) it takes up valuable storage space 2) it will create excessive heat 3) it will be subject to tampering by users when accessing the cabinet.
❖When storing a high concentration of devices that are being charged (such as mobile data collection devices) this creates a level of electromagnetic interference increasing the RF noise floor that can suppress the RFID UHF signal. This may have a negative impact on readability performance especially where device tags are partially obscured by charging cables.
❖When a synchronous network connection (initiated from the TagNet Server) is not feasible to manage the reader directly via a LAN or WAN connection due to network restrictions or QOS, the TagNet Smart Reader Client (SRC) should be considered. Click here to learn more about the SRC and deployment scenarios.
❖This use case can incorporate advanced features such as Employee badge association, that is linking the person who took/consumed the items. This can also include validating their credentials and unlocking the cabinet so that items can be taken. Contact your Stratum Global representative to discuss your specific use case needs.
Configuration Steps to Follow:
2.If managing the reader directly follow the setup steps referenced in the Quickstart section.
Testing Tips and Best Practices:
1.Decide on what tag types you want to start with based on the object type you are inventorying, is it metal, non-metal, packaged item, etc. Refer to this topic on understanding the different tag types available and which one will best suit your material or asset form factors. Note the metal mount tags are tuned to be on a metal substrate to perform to their designed potential, reading them in free space (such as on a strip) does not prove anything with respect to how they will perform when applied to the item.
2.Ensure your IMOVE rules are place to move the tags location when found in the cabinet, and when not found (e.g. Issued).
3.Start testing using incremental steps, put a few tagged items on each shelf and see the results. Don't attempt to put hundreds of tagged items in your cabinet and expect to sort out what is not reading because of tag performance, item placement or antenna type/placement. Once you start seeing results with a small subset of tags you can determine cause and effect when moving your tagged items in different orientations and experimenting with antenna placement. Gradually increase your cabinet population monitoring readability performance at each increment... document this in an spreadsheet along with configuration changes that were made along the way so you have something to refer back to.
4.Ensure you have an RF Power Meter during testing as this is an invaluable tool to validate that your antennas are actually emitting RF and you don't have cable issues or configuration errors. Many customers omit this tool in their planning, it is alike to an electrician attempting to diagnose a power issue without a voltmeter.
5.Use the Event Viewer to see what moves and what doesn't when you take out a few items at a time. Confirm the current location of your test items using the Inventory Inquiry. Return the items to the cabinet and check to see that they have been found during the next inventory cycle.
6.Implementing the above testing activities require that you physically be at the cabinet to gauge cause and effect. Trying to do this remotely can lead to frustration and wasted time as it is vital that you see the difference with every configuration change. Note that every time you make a Reader property change you must restart the schedule so that the new properties are sent to the reader.
ØFor Server managed Readers this it it is done by a submitting a manual Run command and for SRC managed Readers it is done via Rebuild Core Directories switch within the SRC edit page. Also note that TagNet can capture before/after values of reader property changes which is invaluable to see where you started and what has been tested already. This configuration logging can be found here.
7.With respect to tuning when using the triggered approach, the antenna settings can be at 100% power attempting to read everything packed into the cabinet without consideration of signal intrusion into unwanted areas. However if using a non-triggered approach, opening the door can lead to unwanted reads of nearby material and not having an RSSI cut-off may be problematic.
Copyright © 2023 Stratum Global, Inc.