Maintenance at Stihl is organized in two parts. Each production area has its own maintenance teams, which look after the day-to-day business with very good system knowledge. There is a central maintenance pool with specialists who support the teams on site when time is tight or special know-how is required. This makes it easy for the maintenance staff at the Waiblingen and Ludwigsburg plants to exchange information and share experiences, if only because they are so close together. There is a less frequent but no less intensive exchange with maintenance staff in Switzerland, the USA, Brazil or China, for example in workshops or through the employees of the in-house production equipment department. This in-house production equipment department, which develops and implements production equipment and systems for the individual domestic and foreign plants, is one of Stihl's competitive advantages.

In operation, it has the invaluable advantage - at least from the point of view of the maintenance staff - "that the system manufacturer is in-house and therefore quickly available", as Thomas Ruppmann, who has been working in central electrical design at Stihl since 1991, notes. "When we build a system, we are responsible for the entire life of the machine. That's why we have an interest in ensuring that the system is of high quality and causes few problems right from the planning and construction stages." The aim is to achieve the highest possible availability of the production systems. And the version management software 'Versiondog' also supports this. The reason for introducing the tool in 2009 was not so much the stress of searching for the latest software version, but the desire to optimize processes.

Gradually, all systems and areas of production were implemented. Today, there are around 220 users working with the tool at the headquarters in Waiblingen. This is not just about production itself - although production systems are the main focus of 'Versiondog' use - but also the building technology that works with it: Circuit diagrams are stored as well as programs for ventilation or lighting control. In addition, those responsible for quality assurance store the test specifications in it.

Assignment of access rights

The requirements for the different departments and areas are differentiated - the access rights are assigned accordingly, because facility management needs different information than production. It is therefore important that different access rights can be assigned with 'Versiondog'.

Change history: 'Versiondog' uses the change history to identify who, when, what, where and why changes were made.

© Auvesy

Access rights are handled particularly restrictively in equipment construction, especially when it comes to systems with a high level of expertise. This is why the software is not only used in the running plant, as Thomas Ruppmann says: "We use the system in equipment construction as early as the plant creation stage to archive interim statuses." Sometimes it turns out during commissioning that a section needs to be reprogrammed. It is then advantageous to be able to fall back on a previous version.

"We have a tool with which we can access all the necessary information about the system on the spot. And this fast access often also reduces the downtime of a system," explains Ruppmann. With the help of a comprehensive WLAN, not only the program statuses of the respective PLC, but also electrical and pneumatic circuit diagrams, so-called 'quick tips', as the maintenance engineers call them, are available on site in all production areas via the software. In other words, setting instructions or documents for more or less exotic assemblies.

The project was started in the traditional way by backing up the PLC software. The more confident the handling and operation became, the more options became available to the users. The fact that the required editors are also integrated and can be worked with in a familiar environment is also much appreciated. "We only had to define the directory and filing structure. No programming effort was required from the system side," says Ruppmann.

3000 systems archived

Around 3000 systems are now archived in 'Versiondog' in all German Stihl plants, totaling around 7600 components. Three components have been defined as standard for each system: the software - i.e. the control program -, circuit diagrams and documentation. If required, the components can be further structured with subdirectories or supplemented with components for robot or screwdriver control.

A competitive advantage: in-house production equipment construction, which develops and realizes production equipment and systems for the domestic and foreign plants.

© Andreas Stihl AG & Co. KG

A wide range of information can be hidden under 'Documentation': PDF documents as well as Excel tables - anything that can occur as a file format (in terms of control technology). Since the start of data recording, over 46,000 versions have been stored in the archive. The memory requirement on the server is less than 1.5 GB.

The question could be asked whether such packed directories would not result in disruptively long processes when working, which could delay the quick restart after a shutdown. The answer is "No"! Because to save time, Stihl only ever downloads the latest version as standard. "What's more," says Ruppmann, "a comparison of an S7 unit, for example, is very quick."

The systems are backed up daily so that the latest production data is always available. The backups also make it possible to detect unintentional changes. The backups run in the background, so they do not need to be monitored specifically. In the event of anomalies, someone from the responsible team is notified immediately by e-mail.

Acceptance is high

The uncomplicated handling of 'Versiondog' is also reflected in the amount of training required. New employees get to grips with the system after just a short training period and acceptance within the team is generally very high. According to Ruppmann, colleagues see the benefits in their work every day, as all relevant data is available anytime and anywhere.

And what is Ruppmann's assessment of the return on investment? "It's difficult to quantify the benefits in euros, as it's mainly the soft factors that show the added value. Subjectively, it has become much easier with 'Versiondog'." The financial savings were not the main focus during procurement, but rather the transparent and comprehensible documentation. Savings are a pleasant side effect. "There is no longer any need to search for the current software version. You always know where to look." In addition, the regular backups mean you can be sure that the latest version of the control system is always stored.

Data storage has therefore become simpler and more secure. Thanks to the central data storage in a software tool, there is no longer any risk of losing data carriers. According to Rupmann, functionalities such as version comparison are significantly better than the solutions offered by individual device manufacturers.

Author: Silke Glasstetter is Head of Marketing at Auvesy.