Source : RFID im Blick
04-2009
Real time automatic inventory with the new generation of active tags
Olivier Desjeux is CEO of INGECOM, Switzerland
The ERP (Enterprise Resource Planning) is today’s backbone of any modern organization. Based on a central database, the ERP is a unique information system that manages the entire resources of the company. It is a set of different modules that share the same database for the purpose of organizing the workflow. The installation of an ERP into an organization requires a heavy investment in cost and in time availability because managers need to describe what should be the optimum workflow in order to optimize the costs of the internal resources.
The decision to invest into an ERP is clearly a strategic orientation towards the increase of efficiency for all the company’s resources. The purpose of the ERP is therefore to use the cost reduction as one of the vectors for the competitiveness of the company. In this document, only the part of the ERP that used to be called the MRP (Manufacturing Resource Planning) is considered. The MRP or production planning optimizes the utilization of manufacturing capacity, assets, components and any material resources, using historical production data and sales forecasting. The modules related to the administration such as human resources, or marketing, do not deal with the assets involved into the workflow.
Activities of inventory control
One of the modules of the ERP is the inventory control. The activities of inventory control consist of identifying inventory requirements, setting targets, providing replenishment techniques, and recording the inventory balances. For a given workflow, the limit of the ERP is related to the physical inventory of the assets of the company. Any discrepancy between the virtual inventory inside the database and the real inventory of the physical assets brings limitations to the usage of the ERP. Companies that have understood the effects of such discrepancies spend a significant amount of resources to make sure that the physical world remains as close as possible to the virtual world. This is done by inventories. The traditional inventory consists of recruiting temporary workers, shutting down activity for a certain amount of time and chasing all the assets of the company using bar code scanners, or more recently, passive RFID scanners. Both solutions require an adaptation in the workflow, and manual scanning, which still brings a certain level of uncertainty into the result. The inventory done with passive RFID already brings a significant improvement in the process, but the result still has a certain level of uncertainty due to the fact that some tags, without knowing it, may not have been read. This uncertainty is exactly what the inventory is sup-posed to reduce. In some companies this uncertainty is reduced by performing a cross-check of the inventory procedure. Chasing the discrepancies then clearly becomes an endless, very expensive process, which precludes the ambition of cost saving that the heavy investment in the ERP was supposed to bring about.
Automatic inventory in real time
The solution of an automatic real time inventory becomes a dream as soon as the management realizes the value of reconciliation of the virtual world to the real world. The dream can now become reality, at least for the assets of the company. The assets consist mainly in tools, instruments, machines, reusable containers. For all those assets the active tag provides an automatic inventory in real time. The Active RFID Tag has its own power supply, and therefore does not require the electromagnetic field of a reader to send its identification signal. In its simplest form, the Active Tag transmits its message every two seconds, and this message is caught by a simple controller in an indoor radius of 100 meters. The reader looks like a very well known access point, does not cost much more, and can be installed wherever there is a power supply and a network access like the Wi-Fi or an RJ45 socket. The well-known image of a portal through which forklifts need to zoom through is out of the scope of the Active Tag system. This reading through a gate process implies the acceptance of a major risk: the possibility that one or several tags may not be read without knowing it. In laboratory conditions the results are excellent today, but there are always some situations that may happen in real life where the passive tag could not be read. The active tag solution mitigates this risk by the fact that, even in the case where the RF identification is lost, it is very unlikely that all the two second interval transmissions are lost during the whole process of the workflow. This is an important consideration as it allows the inventory to be performed automatically, in real time, without re-engineering the existing workflow. In order for this active tag to be used for this permanent process of inventory, there is, however, a certain number of prerequisites. Ingecom provides the link between the real world and the ERP with its second generation of active tags that fulfil the requisites mentioned. It must be:
- size constrained in order to easily fit the asset on which shall be placed, obviously cost-effective,
- must have the ability to work when placed on metal,
- must have the same battery lifetime as the asset on which it is affixed.