Arun Control Systems was asked to provide engineering assistance by Pirelli Tianjin Cables Company at their manufacturing site in the North Eastern city of Tianjin.
Tianjin is about 90 minutes from Beijing.
Arun Control Systems sent an engineer to help re-commission a control system that included a Eurotherm PC3000 control system, Eurotherm discrete temperature controllers and SSD drives running a monosil cable line. The line had been bought from BICC in Wrexham but was found to have substantial problems when re-assembled in Tianjin.
The Systems Problems
There were a number of issues such as the temperature control loops not operating, e.g. thyristors not firing, no temperature feedback, etc.
However, the most significant issue was the PC3000 local control module had lost it's program and there was no back up of the program. There was, however, a printout of the program (Structured Text and Sequential Flow Charts) although thought to be the original, pre-commissioning version of the system. This implied that the version was not debugged.
There was no documentation with the system of any kind; no specifications, plant descriptions, operating instructions, maintenance manuals, etc.
Our engineer surveyed the situation upon arrival and concluded that there were two options;
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Re-define the user requirement for running the line and develop the software for the PC3000 from scratch.
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Use the program printout to re-enter the software, line for line.and de-bug the program during the testing / commissioning phase.
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Pirelli Tianjin Cables Company suggested a third option was to scrap the PC3000 and it's operator interface and replace it with a Siemens S7 based system.
The Adopted Plan
Arun Control Systems was able to reasonably argue the case for re-entering the PC3000 code from the printout on the basis that the system performed well at BICC, was significantly cheaper than replacing the entire system and could be up and running in less than 1 week.
Despite some scepticism on Pirelli's part about the short timescale, this plan was adopted.
Completed Task
Our engineer completed the recoding in less than 4 days and debugged it in less than 2. The whole line was re-commissioned on the 7th day and has since run without issue. During this week, spare modules for the PC3000 were sourced, purchased and conveyed to Tianjin by Arun Control Systems.
Proposals to replace the system with a Siemens one have since been dropped.
