The initial situation
The company K+S, formerly “esco – european salt company GmbH & Co. KG” is the leading salt producer in Europe. In the largest plant in Bernburg, NaCl has been mined for over 100 years with a degree of purity of over 99%. In Bernburg, industrial salts as well as salt for the food industry are produced. Very large quantities are shipped by rail as loose goods. Furthermore, very large quantities are also packed as big bags and bagged goods. These are palletised and temporarily stored in a high-bay warehouse for dispatch.
The prepared and conditioned salt is packed and palletised on up to 15 production lines. The production lines are to be connected to SAP in future.
The requirement for A+K
K+S commissioned A+K to create a consistent concept for introducing an MES.
This included replacing five S5 945 CPUs with a modern S7-416 CPU, introducing a Scada system, taking over production orders from SAP, setting up order management for the production lines, feedback of production figures, the fully automatic supply of the line printers by the new MES and introducing data acquisition for all lines for an OEE based on SAP.
The existing software of the five S5 945 controllers could be ported partly automatically, but partly it had to be reprogrammed in S7. For each line, one or sometimes two new operator panels were developed.
An order management system was set up on the basis of the Scada Plant IT system. The orders were transferred from SAP via an interface server and output in the MES. The plant operator can now start a production line; if salt is available, and the line starts producing. The production can be carried out in exact quantities, but remaining salt is still packed afterwards. Once all the salt has been packed and the last container palletised, the production order is automatically completed.
The line printers automatically receive the necessary data for each production order and apply them to the articles.
The process data created during production are reported to SAP. On SAP these data are used for an OEE evaluation.
The in-house test
A+K completely tested the MES in the Herzogenaurach office. The PLC software was tested with simulators. A mock-up was also created for the interface tests to the SAP interface server.
The new MES was installed on a server and the operator stations and linked to the new S7 400 automation device.
The existing five old S5 945 PLCs were all equipped with one PROFIBUS master module each. The new S7 400 automation device was also equipped with five PROFIBUS master modules.
The new operator panels were connected to the five existing PROFIBUS. They were given free PROFIBUS addresses to prevent collisions with the old devices.
Tests were conducted over two weekends. For this purpose, the five PROFIBUS connections were transferred from the five old PLCs to the five new PROFIBUS masters of the new S7 400 controller.
Now test production could be started on all production lines.
After the end of the second test weekend, the new MES went into regular operation.
The retrofitting of existing production plants with a manufacturing execution system (MES) is highly feasible with modern technologies.
The porting of S5 legacy code to modern S7/TIA code is, as always, highly dependent on how the S5 code was programmed at the time.
The tests in the office with corresponding simulators/mock-ups are essential in order to limit the commissioning process to as few weekends as possible.
When introducing an MES, it is advisable to update subordinate control systems as well.
- Creation of an MES based on ProLeiT Plant IT
- Supply of the MES with orders from SAP
- Supply of the production lines and machines with order data
- Supply of the line printers with order data
- Precise manufacturing
- Reporting of production data to SAP for OEE Replacement of five S5 945 units by one S7-416
- Creation of central plant visualisation with reporting system based on Plant IT
- On-site operation with Siemens mobile operator panels
- Integration tests with all parties involved on two weekends
- One week start-up support for optimisation and retraining of operating personnel