Abstract:

• Monitoring of compressor stations located in a plant for forming thin sheet metal for car bodies
• Detection and signalization of faults for rapid elimination
• JetControl 241 with web-server and JX-SIO peripheral modules
• Integration into the existing Ethernet network
• HTML-based visualization with data integration via SSI
• Acquisition of analog and digital signals with calculations for preventive maintenance
• The controller can send e-mails to service personnel
• If a web browser has been installed, the plant status can be monitored from any PC via Intranet by entering the corresponding IP address.

The Application:

In this company, there would be malfunctions in the compressor station occasionally. This would at times cause production standstill. Malfunctions would be signaled by a simple flash lamp, which could not acquire all plant malfunctions, though, or which would - on the other hand - be activated at certain operating statuses without there being any malfunction. Further, the flash lamp being active would not be recognized, when the persons responsible for maintenance were just being on their way in the company.

This caused the company to establish a supervisory control system for the compressor system being able to acquire and recognize malfunctions immediately and thus make immediate correction possible.

Criteria in Favor of Jetter AG:

After extensive inquiries made by members of the company, the JetWeb technology has been selected as the only apt system. These were the decisive factors for this decision:

• Cost effective solution
• Both digital and analog signals can be acquired
• Other than with standard alarm indication systems, any kind of calculation can be carried out, even with analog values (e.g. alarm indication, if the pressure has decreased below a certain value)
• The "JetSym" programming language for PLC programming can easily be learned (it is much easier than programming a classic PLC control system)
• The programming software in the demo version is fully workable up to a 4k program code; this is favorable for doing initial tests
• The controller can easily be connected to the already existing Ethernet
• HTML pages programmed by the user and stored to the memory of the controller can be viewed from the Intranet in any PC. For this, just call up the IP address of the start page in the Web browser (e.g. http://149.211.150.250).
  149.211.150.250).

The control systems being able to send e-mails to any mail address have also been a decisive factor.

Experiences and Benefits:

Since the e-mail function was implemented, a great number of malfunctions has been reported automatically. Localization and preventive repairs of the reasons of compressor breakdowns due to occasionally occurring malfunctions (e.g. intermittent electrical contacts causing total component failure), have been made possible by transmitting the status of the plant by e-mail for evaluation.

Many compressor failures could be mended so quickly, that the compressor would be online in no time. This way compressed-air supply failures could be prevented.

The most critical malfunction was a total breakdown of the compressor station. The main pressure sensor had failed. This caused the plant control to refuse all compressors supplying air. This caused the pressure to decrease, which in turn caused the Jetter control system to report the malfunction to several members of the maintenance staff. Because they were able to comprehend immediately the severity of the malfunction from the transmitted status report, they immediately notified a colleague being near by phone. Three minutes later, this colleague switched the compressors to manual operation - just before the pressure would have decreased to a critical level.

Components used:

• JetControl 241 (W)
• JX-SIO peripheral modules
• Digital and analog I/Os
• SSI for entering the controller values into HTML pages