What is the most appropriate technology to use to track assets and inventory in real time in a factory environment? RFID, BLE or is there another technology that can be better?
There is no correct answer here, and most sources you will encounter are simply stating the "easiest" answer without a context in reality. The reality of it is that, it all depends on what you need to track, how accurately and at what cost per area.
Here’s a way I’ve found to categorize tracking requirements in the field that then helps determine the correct solution.
Start by What Needs to Be Tracked.
Most often the mistake people make, is that they pick a technology and then find every way to make it applicable to any problem, which will eventually leave them at the losing end of the game. Rather start by identifying your requirements and then placing them in these categories:
- Bulk inventory tracking: Pallets passing a door, or containers entering a zone. You just need to confirm if a item has passed a particular location, not what route it took to get there.
- Zone level detection: Locating a person or equipment within a specific area, for example knowing the approximate area in the facility where the worker or equipment is. This require reasonable precision at a relatively lower cost.
- High Precision: Forklift and pedestrian detection within very close proximities, locating an item with in centimeter accuracy (necessary for AGVs and some other robotic equipment). This requires a very specific smaller area for its application but demands the highest accuracy and therefore cost.
Once you have properly defined which category each requirement fits into, the technology selection process become far more easier:
- Passive RFID: Best for Bulk inventory tracking as defined above. It is extremely cost efficient for per tag, requires no battery replacement and works well for identification and tracking at points and transitions. However, RFID doesn't work for real-time positioning. It works based on event.RFID answers if the item was at A but not how it moved from B to A.
- BLE (Bluetooth Low Energy): Works well for Zone Level detection. More cost efficient at scale than UWB, but with limited precision as compare to UWB. It is ideal for worker locating, generalized asset tracking, and proximity-based notifications. For most manufacturing plants, BLE is often the solution of choice to cover a wide area and other higher precision solutions supplement this requirement.
- UWB (Ultra-Wideband) and RTLS: These are for the High Precision requirement. If your operation needs sub-meter precision for collision detection (forklift-pedestrian), pathway validation of AGVs, pinpointing equipment within a kitting or assembly area, etc., then UWB and other RTLS solutions come into play. Although it comes with higher costs due to higher infrastructure complexity.
- LoRaWAN: Used for low power long range communications, mainly useful for sensor-based tracking like cold storage monitoring, YARD to Plant communications etc. It’s not ideal for in plant real time positioning.
For the average manufacturer today:
It would never be just a single solution, the most common and practical solution consists of RFID for the inventory checks and tracking at transitions, BLE for overall zone level monitoring of assets, and UWB/RTLS for the specific areas or use cases where sub-meter accuracy is absolutely essential. It’s more often the integration layer, i.e. Consolidating the data from the different technologies into a single system that is crucial and can deliver real business value rather than selecting the first or best sensor technologies.
I would recommend you check out PlantLog AI; they’ve developed an integrated platform for in-plant logistics tracking, where all these technologies are unified and connected with the existing ERP / MES systems, which will simplify your integration efforts a lot if you are at the planning stage.
Hope this explanation is helpful. Feel free to reach out with any further questions, and I can help dive into specific use cases for your factory.
