Article - Installation audit for Soporcel

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Date: July 2007

In this article I want to enlighten you with what goes on during a PROFIBUS installation audit. As an example I will take the paper-mill Soporcel in Portugal (Europe) which we audited some time ago. Soporcel has an enormous new recovery boiler which is required for the paper fabrication process. This project was a mutual cooperation of automation companies all over the world. For PROFIBUS this was an important reference project, because it proofs the acceptation of bus technology in pulp- and paper applications. PROFIBUS was already used for pre-processing, but never in such a large primary process.

Summary of equipment
- 5 Honeywell DCS systems
- 147 DP slaves (Siemens-ET200M/Simocode, Auma-actuators and ABB-drives)
- 470 PA slaves (E+H and Siemens)
- 58 HART instruments, coupled through I/O cards.

The companies who were responsible for the engineering, panel building and installation, started with a training course at PROCENTEC in The Netherlands for a week and used the acquired knowledge to do the project. After everything was programmed and installed, it was PROCENTEC's task to audit the installation. Two engineers went to the site and inspected the schematics first to get an impression about the installation. They split up the work and went with 2 teams of engineers into the field to inspect/measure the installation. Timing was crucial so the use of proper tools was very important. With the ProfiTrace Analyzer, oscilloscope and the PA Probe more than 470 PA instruments were commissioned in less than 2 days and these tools brought a lot of hidden problems to the surface:

1) Address swap
The addresses of instruments of the same type have been swapped. This means the wrong process value enters/leaves the control system. This is very difficult to detect. You can only see it when an instrument is powered down and you check in ProfiTrace which address "falls-out".

2) Double addresses
Two instruments accidentally had the same address and because of this they cannot communicate. With ProfiTrace this is easy to detect. The client has to decide what the correct address should be.

3) Instruments with a damaged bus interface
Several instruments had damaged electronics which were constantly transmitting corrupted signals. This had effect on the entire segment. When the instruments were replaced everything was OK again. With ProfiTrace and the oscilloscope this was easy to detect.

4) Contact problems
A couple of connectors did make proper contact because the screws have not been tightened sufficiently. This was easily detected with ProfiTrace. The oscilloscope was used to pinpoint the exact location.

5) Too many termination
The termination switch of some devices was accidentally set to ON. Some segments had 6 or more terminations active, which corrupted the signals. This could only be detected with the oscilloscope.

All of the deviations we have detected at this site have to do with cabling. This is most of the time the same issue. All issues were solved directly by the team of engineers that went with us and the installation is now running on 100% with full availability of all instruments. After this successful project, more plants that belong to this organization will be automated with PROFIBUS.