The first experiences at a pharmaceutical plant of Aventis

Aventis Pharma Deutschland of the sanofi-aventis Group is constructing two new production lines, based on fieldbus technology, for two preliminary substances of the novel antibiotic Ketec for treatment of acute respiratory infections. The engineering group of Aventis single-handedly managed the project and implemented the automation with the support of Siemens as their general engineering consultant. 'The greatest challenge of all was to retrofit a running production plant', says Bodo Bartscheit, the process control project manager of Aventis. As a part of the project the test laboratory of Infraserv Höchst Technik was assigned to commission the fieldbus technology. The Ketek plant is one of the first plants to be set up based on the 'Fieldbus and Remote I/O System Comparison' (FuRIOS) study.

Project

Top

At the general assembly of the 'Association of Users of Process Control Technology' NAMUR in Lahnstein, Germany, at the beginning of November 2004, Sven Seintsch, by representing all participants in the project, drew a first conclusion about how the FuRIOS has been put into practice. Mr. Seintsch is a member of staff of the Infraserv test laboratory as well as IGR (Industrial Practices Interest Group) expert consultant for fieldbus technology and member of the NAMUR fieldbus working group. Two years prior, Dr. Thomas Tauchnitz, head of technology and projects at Aventis Pharma Deutschland, had introduced the FuRIOS study to the same auditorium. The aim of the analysis was a study of feasibility as well as cost-benefit aspects of the fieldbus from the user's point of view. The results of the system comparison as well as the extensive laboratory tests performed by Infraserv Höchst Technik formed an important basis for reaching a decision on the new fieldbus plant of Aventis located the industrial estate 'Industriepark Höchst' near Frankfurt, Germany.

Fieldbus in action

The current implementation uses Profibus PA. However, according to FuRIOS, Foundation Fieldbus H1 could be used equally good.
At first, Aventis and Infraserv Höchst Technik built a test segment under laboratory conditions to check the technology thoroughly and to eliminate potential problems in advance. Within this pilot project the complex experimental set-up has proven extremely useful in many ways. One of the major targets was the development of a commissioning strategy, in order to test the communication between the different components and to train the installation companies on using the new device technology .

With the exception of the safety related signals, which were still wired conventionally, all process instrumentation communication is working on fieldbus. The plant consists of 11 process-near components with 22 Profibus DP segments, to which 250 motors and transverters are connected. The two new production lines comprise a total of 200 Profibus PA segments with 1,600 Profibus PA devices. The conventional intrinsically safe valves and their end position signalling are coupled to the bus by 190 Valve Boxes, and 20 Sensor Boxes read the intrinsically safe binary switch signals. 50 Segment Couplers provide a faultless transmission of signals between Profibus DP and PA segments. The modular Segment Coupler's Power Link Modules supply high current to the Profibus PA segments which then is distributed to the individual field devices by 470 fieldbus barriers from Pepperl+Fuchs. With the given Zone 1 topology, the use of fieldbus barriers is a decisive criterion for operation efficiency. Typically, 12 devices are connected to four fieldbus barriers per segment and approximately 60 to 70 field devices to one Segment Coupler. Thus Aventis does not use all the connection points of the fieldbus barriers and leaves approx. 20% spares to extend the production lines later without rewiring. The plant integrates 15 different device types of multiple vendors like ABB, Endress+Hauser, Krohne, Knick, Pepperl+Fuchs, Samson and Vega. Plant commissioning was done directly in the DCS system, using a FDT/DTM (Field Device Tool / Device Type Manager) based integration tool.

The FDT/DTM problem

'Generally speaking, the FDT/DTM technology is good and the manufacturers should continue to follow its development since it is not yet at its prime', comments Seintsch and continues: 'Maybe you do not always have to be among the first'. As this technology for device integration is a relatively new kind of technology, the Ketek plant posed a learning curve for both users and manufacturers. 'FuRIOS has predicted teething problems during the first project and, indeed, problems cropped up. However, they mainly occurred during device integration which was not in the scope of the system comparison study', explains Seintsch. One thing is crystal clear: The start-up problems with device integration has nothing to do with fieldbus. In conjunction with the device manufacturers and the Infraserv test laboratory, Aventis had to overcome several obstacles. But now it is almost done. Today all of the devices except one are operating smoothly and the project responsible persons are confident that they will also overcome this last hurdle.

Clear path for Profibus PA

'We can already say today that the Ketek project confirms the FuRIOS study with regard to faster commissioning and easy installation', says Seintsch. The basic general conditions: a different way of thinking during planning and installation as well as qualified and specially trained personnel. It is also clear that fieldbus technology alleviates the confirmation of intrinsic safety by using the FISCO model. This way, instead of calculations filling up folders, only a few parameters are to be documented. The life cycle costs, however, cannot be compared to the study yet, as they will become apparent during long-term operation only. Also for confirmation on FuRIOS's expectations on additional benefits of fieldbus technology in regard to maintenance and diagnostics a certain amount of patience and time is required, too.
All participants in the project are asking the manufacturers for a redundant coupler, higher output current for the Profibus PA lines and additional types of field devices in two-conductor technology. A definite 'yes' for fieldbus by all users of process automation technology could possibly speed up the development of new components. At least, it would be an unambiguous signal for the manufacturers that it pays off to continue investing in this technology. If it were for the experts of Aventis and Infraserv Höchst Technik, future projects at the Frankfurt location would be equipped with fieldbus exclusively. However, solutions for long-term support, a guaranteed downward compatibility and software maintenance must be optimized on the part of the manufacturers. One step has been taken in the right direction, several projects currently in planning or installation phases confirm the increasing acceptance of fieldbus technology in the chemical and pharmaceutical industry. Maybe the expectation manufacturers have had for many years will finally be fulfilled - the breakthrough of fieldbus technology in the process industry.

Result

Top

Fieldbus barrier it is!

The breakthrough regarding device connection methods were the fieldbus barriers. This was one of the conclusions of the working group 2.6 'Fieldbus' at the 2004 NAMUR general assembly. Fieldbus barriers play a major role in all three experience reports presented by DSM, Infraserv/Aventis and Novartis. Back in 2000, before the fieldbus barriers were broadly available, only few devices could be operated at one segment, whether Profibus PA or Foundation Fieldbus H1, if the fieldbus layout was of the conventional kind with the barrier in the control room. With today's typical topology, which the NAMUR working group recommends as 'best practice', the installation is based on fieldbus barriers, since they reduce wiring, planning and installation costs and thus are the main contributors to the operating efficiency of the technology. The fieldbus barrier's output lines guarantee higher flexibility, more devices per Profibus segment and increase of plant availability. The outputs of the fieldbus barriers are individually short-circuit current limited and intrinsically safe according to both Entity and FISCO - another advantage when planning or operating fieldbus plants, as this makes the fieldbus suitable for all currently available devices. Furthermore, the fieldbus barriers enable the disconnection and exchange of the devices during operation and thus facilitate service and maintenance.