Programmable Logic Controller - Material Flow System
Application component: Material Flow System
App type: SAP GUI
Description:  The material flow system (MFS) enables you to connect up an automatic warehouse to Extended Warehouse Management (EWM) without the need for an additional warehouse control unit. You can set up the MFS in such a way that warehouse tasks (from an identification point to a storage bin in an automatic high-rack storage area, for instance) are subdivided into smaller tasks. These are passed on step by step to the programmable logic controller (PLC) responsible in each case using telegram communication. The putaway and removal from storage of handling units (HUs) can thus take place without the use of another software system. You can define capacity limits for communication points (see Communication Point), conveyor segments (see Conveyor Segment), or resources (see Resource). The EWM system then holds back tasks for the PLC as soon as these limits are exceeded. The same applies if the PLC reports that one of the individual elements of conveyance (vehicles, legs, communication points) are subject to malfunction. A warehouse management monitor that is supplied as part of this package enables you to track, evaluate, and influence the process. 
Key features:  If you use EWM to manage an automatic warehouse, you can use the following functions: Automatic identification of HUs using scanners on the automatic storage retrieval facilityAutomatic diversion of HUs that cannot be stored (incorrect contours, excessive weight, unidentified)Fully automatic putaway of HUs in the storage bin using any number of interim stepsThese interim steps are represented by communication points. Malfunctions reported by the controls taken into accountCapacity limits for communication points, conveyor segments, and vehicles taken into accountReduction in empty traveling paths for stacker cranes through interleavingGoods to man picking principleStock available for deliveries during transportation within the systemStable telegram communication between EWM and PLC using parallel, bidirectional communication channels The warehouse management monitor provides you with the following options: Tracking of current state of systemEvaluation of telegrams and response timesDetermination of current location of HUs and identification of associated warehouse tasksDetermination of telegram traffic relating to individual HUs or warehouse tasksStopping or restarting of communication with regard to individual controlsLocking of communication points, segments, or resourcesResending of telegrams where necessaryManual confirmation of warehouse tasks You can call up logs for exceptions using the alert monitor (see Alert Monitor). The system generates these logs if communication with a PLC was interrupted and EWM initiated an automatic restart of the communication channel. You can link these exceptions with follow-on actions (such as notification of a control station). A further evaluation allows the accessing of system logs (see Analyze Logs) by the system administrator. An example of something that might be logged by the system is when a warehouse task pending transport was not sent to the PLC (due to insufficient capacity at the next communication point or due to a malfunction, for example). For more information, see MFS in the Warehouse Management Monitor and MFS in the Alert Monitor. For a better understanding, the graphic below illustrates a possible automatic storage retrieval system in an example warehouse:  This example warehouse consists of an automatic high-rack storage area with three aisles and automated putaway and removal. A distribution trolley links the putaway and picking area with the high-rack storage area. From the MFS standpoint, this warehouse is operated with four controls. Three are for the stacker cranes (green) and one is for the distribution trolley and the conveyor lines of the preliminary (prestorage) zone (blue). The warehouse has a single depth; the distribution trolley and stacker cranes each have just one load handling attachment (LHA). The following graphic shows an example of the material flow in this example warehouse:  This example comprises the following processes: PutawayRemoval from storage of full palletsSupplying the picking binPutbackConveying off the pick-HUDiversion to clarification bin