By Bianca Scholten
Have you ever seen the painting by René Magritte called La Trahison des Images [The Treason of Images]? The picture is of a pipe with the text below it reading, Çeci nest pas une pipe. [This is not a pipe.] Magritte is right, of course, because indeed it is not a pipe. It is just an image of a pipe.
In the same way, the data in ERP systems are just images of the real situation within the enterprise. But how realistic an image are they? By visiting some European and American industrial enterprises, I have learned that most of them feed their enterprise resource planning (ERP) systems with averages and estimates instead of with actual data, a fact that opens up wide vistas for business process improvement.
In recent decades, industrial companies have invested much time and money in ERP systems and in automation of the process control layer. In between these two layers of automation, theres a nobodys land usually called the MES (Manufacturing Execution System) layer. MES concerns the activities that take place within a production department; for example, preparative tasks, such as detailed production scheduling and recipe management, but also data collection, tracking and performance analysis.
When you take a close look at such functions within plants, in general, you will encounter a primitive situation. Island automation is everywhere. Most of the factories use MS Excel for detailed scheduling and reporting, and they use MS Word for management of recipes and SOPs. Sometimes plants use more advanced applications, but in that case, these are built by different suppliers and they are not integrated. (See Figure 1.)
Typical European and American plants are islands of automation where a Babel of languages are spoken, impeding data and information exchange.
The lack of insight also becomes painfully obvious if you take a close look at planning issues. The ERP system does provide a production plan, but this usually is not adjusted to the finite capacity of the production lines, nor has it taken into account efficiency. Thats why, in almost every factory, you will encounter planners who work in Excel. They are people who have a huge amount of knowledge. They cannot ever be ill or on vacation. The factory is completely depending on them, so they feel highly appreciated. In the meantime the general manager has a hard time getting the information he needs and is left wondering who really is the boss .
Another disadvantage of the current situation is that the operators cannot concentrate on their core task: controlling the process. Instead, they have to spend a lot of time transcribing data from one system to the other, an error-prone process that leads to data being known in other departments and systems only hours or even days after an event occurs, at which time it may be too late for corrective action.
Plants that use systems that are not integrated also have significant master data management issues. When production is using raw materials from new vendors or when new recipes are introduced, then adjustments to the master data in all the systems are needed. This process takes time and may lead to data inaccuracy. Sometimes it leads to the procurement of the wrong materials or the production of final products that do not comply to specifications.
In order to avoid that, operators have to spend a lot of time doing administrative tasks. In many enterprises, it is common to report an average amount of raw materials back to the ERP system and the average production result instead of actual kilos or liters. In that case, depending on the industry, daily, weekly or monthly inventory stock levels have to be counted or measured, and the administrative stock level has to be corrected in the ERP system. Meanwhile, the administrative inventory is not reflecting the physical stock, conceivably leading to production stops, because the right raw materials are not availableand no one catches the discrepancy until production stops, and the costs start adding up by the minute. Or, more likely, hundreds of thousands of dollars in unneeded inventory are kept on hand, just in case.
This unwanted situation is a thorn in the side of many plant managers. They do understand that improvement of automation and communication between systems may help solve such issues. But who can they turn to? Factory automation traditionally is the domain of engineers, who program in ladder diagrams, function blocks and SFCs. But the network on which those ubiquitious reporting tools, MS Word and MS Excel, are based is the responsibility of the IT department. And these two departments might as well be in different countries, with different languages and cultures.
Collaboration seems like the logical answer, but in the Nobody Land of MES, thats not so simple.
MES: IT or Engineering?
For decades, factory automation has been the domain of engineers. They have programmed and maintained the PLCs that control the production lines. Later, SCADA systems were added for process visualization. SCADA suppliers started to offer more and more functionality, such as historians, that can store huge amounts of data. They also developed functionality for recipe management. Over time, more and more IT-like systems were provided by these traditional control suppliers. And these systems require different, IT-like knowledge from the engineering department.