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Minimising disturbance to continuous manufacturing processes is crucial when choosing SCADA software to replace legacy control systems.  For complex systems choosing the right replacement can involve considerable investment in both time and money.

A major manufacturer of Polyester Polymer and supplier of bottle grade PET resin recently solved this problem at their polymer manufacturing facility at Bellville, Cape Town, South Africa. The plant was built in the 1970’s with 20 SCADA systems connecting to Allen Bradley hardware typically with 5,000 to 30,000 signals per system.

The major challenge faced was replacing these systems without operational shutdown.  In normal running the plant operates continuously 24/7 with planned shut downs once every 3 to 4 years. If production stops for any reason 14 days is lost in the shutdown – start up process.

The company invested considerable time and effort looking for a suitable replacement. During that time several software packages were evaluated and discounted. 

The answer came with the SLANG Sequence Control Language in Prodigy SCADA software. Considered to be a unique facility by the on site team of developers SLANG has allowed them to successfully migrate the plants control systems to the new software.

Initial contact was made in 2006 and after initial evaluation the on site team developed the first replacement system. Underlining Prodigy’s ease of use this was achieved without any training, relying solely on the software documentation and Prodigy technical support

In May 2008 another larger 25,000 tag system had been completed and commissioned.  To date both systems have run without fault with 100% uptime and no disruption to the manufacturing operation.

SLANG is an interpreted language in which each instruction is immediately translated and acted upon by the computer.  This means that code can be developed, tested and run without the code needing to be compiled.

The way SLANG is designed makes it easier to understand than computer coding languages. You do not need to be proficient at programming to be able to create complex control sequences and this makes it very engineer friendly.

July 2008.