Understand SAP EWM
The concept of Layout-oriented Storage Control (LOSC)
Note: This post belongs to the blog-series ‘Understand SAP EWMThe concept of Layout-oriented Storage Control’. The purpose of these series of blog-posts is to explain the concepts of the core features of SAP EWM in a simple way. We want to focus on the basic understanding rather than the smallest details.
For the beginning, let us stay away from the system and try to understand how Layout-oriented storage control would look like in real life.
Imagine you go for a city trip in order to see a famous site. You arrive by train and need to find a way from the train station to the site.
The site is about 10 km away from the train station and in addition to this, there is a river crossing the city. So there is no option to reach the site on foot. There might be a bridge across the river but you are not sure.
So the first thing you can do is to go to the closest taxi station and tell the driver that you want to see this famous site. We have the first movement here: Train station to taxi station using your feet as the mode of transport.
The taxi driver is happy to give you a ride but unfortunately tells you that there is no bridge at all so the only thing he can do is to drop you at the landing pier of the ferry. You agree as you have not other option – it is too far for walking. So we see the second movement here: Taxi station to landing pier using the taxi as the mode of transport.
Having arrived at the landing pier the last step is easy. You take the ferry and arrive at your final destination. The last movement from landing pier to the site uses the ferry as the mode of transport.
To sum up –
We could not go directly from train station to the site so we had to split our path into different sub-paths. When we started the first sub-path we did not know how exactly we would reach the destination but people on the way (e.g. the taxi driver) helped us.
So how would that look like in a warehouse now?
We make it short and easy again –
We receive a pallet and want to store it on a bin in our automated storage & retrieval system. Our ASRS is nothing than a pallet rack which is operated by a couple of automated storage and retrieval robots. So no option to putaway with the forklift which is the only resource which we have in the receiving area.
We create our initial warehouse task from the receiving area to the destination bin in the pallet rack but based on the LOSC customizing the system knows that this WT cannot be confirmed in one step. Thus, it is created in ‘waiting’ status and a seperate WT is created to send the pallet to the handover place of the conveyor. This WT is using the forklift as the resource to process it.
Having arrived at the conveyor the system checks again whether a direct movement to the destination bin is possible or not. We need our storage robot for the putaway so the next WT is created to send the pallet by the conveyor to the ASRS handover. Here we have the option to communicate directly with the PLCs using the inbuilt MFS component of SAP EWM. Our second WT uses the conveyor as the resource to process it.
Once we reach the ASRS handover and the storage & retrieval robot picks up the pallet the system checks the LOSC customizing again. This time there is no intermediate bin left so we activate the first WT, update its source bin and conduct the movement. Here we use the storage robot as the resource to process it.
Just a quick look at a sample customizing – again a simplified view as we are not interested in all details and possible configuration options at this point.
For our example flow we would need at least two records.
The first record would have the receiving area as the source storage type and the pallet rack as the destination. The intermediate bin for this records would be the conveyor handover.
The second record would have the conveyor handover as the source storage type and again the pallet rack as the destination. The intermediate bin for this record would be the ASRS handover.
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