Logistics processes are as different as the products that are handled in this process. Starting with the framework conditions for storage, product properties, individual weights, packaging units and product dimensions are also different. In most cases - and here all applications are identical - the processes of storage, transfer, retrieval, picking, packing and dispatch are all about the exact and precise implementation of the respective order. This is precisely where the use of weighing technology comes in. It is important for every logistics planner to ensure that neither incorrect deliveries in relation to the specified target quantity nor article mix-ups occur.

Depending on the budget and company size, the question arises as to whether a system should work offline or online. In the online version, the target weight of the article is loaded from the article master during the processing operation. Prerequisite: The article weight must be up-to-date, batch-managed if necessary and precise. Users know from experience that in order to avoid errors, a special work/inspection station is recommended at which all items are recorded completely and correctly in the incoming goods department. This ensures that downstream work processes that access the master data deliver exact results.

Exact item weight is stored
This is possible with Rhewa counting and weighing systems with different resolutions. If centralized master data maintenance appears too costly or time-consuming, the piece weight is first determined in the respective process step, such as storage, transfer and picking. The scale guides the operator, automatically switches to the appropriate weighing platform if required and enables the piece weight to be determined. The disadvantage of this solution is that the operator represents the main risk - he must not make a mistake.

Regardless of which safety functions the individual user company is aiming for, it is crucial for the implementation that the scales are in permanent communication with the WMS. This can be realized either via LAN or WLAN. With the DataLog communication software as a service, the data relevant to the scales is provided in an SQL table. The scales write the result data to a separate data table on the SQL server via the interface. The entire communication is controlled by DataLog as a service, eliminating the need for a complex and time-consuming connection to the WMS or ERP system.

Important aspect: scale operation
The next project planning question relates to the operation of the scales: Either it is carried out on the operating screen of the WMS so that the scale display (evaluation device) plays a subordinate role for the operator. In this case, the combination of pick-by-light and piece weight check can be combined. If the operator picks incorrectly or makes a mistake with the quantity, an alarm is triggered immediately at the latest when the part is placed in the container on the scale.

The prerequisite is that each picking process is coupled with weighing, so that only pure net weight values are checked. This is only feasible with a correspondingly high resolution scale, which may be integrated into the picking table or directly into the conveyor system. With an appropriate design, 30 kilograms can be weighed and an accuracy of one gram can be achieved. If the parts are lighter, two weighing platforms are used. Either the operator decides what is to be weighed and where, or alternatively the scale is specified to the operator by means of master data maintenance so that it automatically switches to the stored weighing platform.

Or you can dispense with the cost-intensive monitor workstation and use an evaluation device with the necessary display options. In this case, barcode readers, label printers and other identification devices are connected directly to the scale terminal.

For projects without an IT connection, error minimization is usually just as important. However, the entire effort for providing data in the WMS/ERP and processing the incoming data is eliminated. In combination with a simple label printer - there are no restrictions when connecting to Rhewa terminals - and an EAN 128-capable barcode reader, a high-performance solution is created. Empty containers are provided with a barcode for tare at the touch of a button on the scale. For deliveries/storage, the unit weight is determined once for the item and printed with the item number in a functional barcode, which is then also attached to the container. This automatically solves the batch issue, as the barcode is generated for each batch. The size, scope, label material and content of the labels always depend on the customer's specifications.

Fast stocktaking, fast picking
By scanning the two barcodes, the contents of a container can now be specified in less than two seconds. Stocktaking couldn't be quicker. However, as stocktaking only takes place once a year for each item, the advantages are clear when picking. By scanning the article barcode, the scale can be set to target weight mode (target weighing). All the operator has to do is enter the target quantity. The scale terminal guides him and sets appropriate signal ranges so that the operator cannot release an under or over delivery of an item. With a special power supply on an ergonomically designed transport trolley, the user moves the scale through the warehouse and picks directly at the storage location, thus preventing "empty runs". The possible solutions shown here can be combined, but there are also many other variants and customized solutions.

About Rhewa
As a manufacturer of industrial weighing technology, Rhewa specializes in the development and manufacture of precise and durable system weighing technology. The experience gained from classic counting scales flows into the design of quantity and weight-dependent article movements in intralogistics. In addition to the measuring technology, the actual workflow is often decisive for the precise determination of quantities. At the Mettmann site in the Rhineland, weighing technology is produced that bears the title "Made in Germany" and has been proving this throughout Europe for over 115 years.