Discover SAP EWM MFS

The Identification-Point

This blog is part of the series ‘SAP EWM meets Automation – Discover EWM MFS’ and also tackles the hardware but mainly the software side of this thing that we call ‘I-Point’ (Identification-Point) in the area of EWM MFS.
Note that I will not explain every MFS object again here. In case you are not familiar with EWM MFS already, I would recomment reading the EWM-PLC integration blog post at first.

As with all posts of this series, the content provided here has been created in cooperation with the SAP EWM team at Swisslog. Feel free to visit their website in case you want to learn more about the services offered by @ Swisslog or to browse open positions within their EWM team!

Agenda

– Overview process flow at the I-Point
– The hardware of the I-Point
– The EWM part of the story

As an introduction, let us have a quick look at a high-level overview about the process/context we are talking about within this blog post. To have a practical context again, we assume that we are looking at a pallet which is moving on a conveyor, passing an I-Point. Physically, it could look like this:

The following things will happen now: – The HU/pallet arrives at the I-Point and is detected by the sensors – The sensors trigger the activation of other sensors, scales, scanners etc. – The subsystem (PLC) collects all relevant data (e.g. results of the weighing and scanning events) and processes it based on the logic sitting in its memory. As a result we have a string of data which is transmitted to EWM as a telegram – EWM receives & processes the telegram and in turn sends another telegram in order to initiate the follow-up process (e.g. creates a task to move the pallet to its next destination and sends the telegram for this task to the PLC) – The PLC receives the telegram, processes it and e.g. decides to start the motor unit for the conveyor moving the pallet away from the I-point:

Note that this process will be slightly different in a fast moving case conveyor environment but for the sake of understanding the I-Point concept in general, we will ignore this for now. Having a rough understanding of the process we are talking about, let us now have a quick look at the hardware of a typical I-Point. Being used for identification, an essential part of an I-Point is a device which reads data from the object/HU passing by. This could be a barcode scanner reading a label or a RFID scanner reading a tag or any other kind of identification method. In addition to this we have plenty of optional checks/devices installed at an I-Point. Examples are sensors for profile checks (e.g. length, width, height), scales for weighing or tunnel/roller checks to validate the quality of a pallet.

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On the other side – and a bit more interesting for us – we have the software. Here we are mainly talking about the creation and processing of telegrams by the PLC/WMS (here SAP EWM):

Starting with the creation of the telegram by the PLC, we can separate the high-level steps on EWM side into the following ones: – Receive a telegram in the inbound buffer – Find a MFS action function module to process the data – Execute this FM – Close the FM with the creation of a follow-up action / task

Step 1 can be subdivided into the following steps: – The data is received via ABAP Push Channel or a TCP/IP-RFC converter like PlantConnectivity, from where FM /SCWM/MFS_RECEIVE2 is being called – The FM writes the data into inbound buffer table /SCWM/MFSTELEQ – F