Case histories

Case history one: Crane control

In the pictures below, the original source code(Instruction List) is installed in the PCD controller on the left and the model with the converted code (Ladder/FuPla)) is shown on the right. To the right hand side of the picture are the electrical servo motors with potentiometric or digital encoder feedback and these simulate the servo valve amplifiers for Slewing, Boom and Hoist functions.

The original crane also featured novel functions that were not working correctly but with modification to the model's software, are now functional.

This is the third model that we have created for this client and the end result was demonstrated to their engineers for approval (FAT) with all the equipment including Digital & Analogue simulators designed and built in our workshop.

Case history two: Waste energy conversion plant

Methane gas is extracted from a landfill site and pumped into seven 1MW generators and returned back to the National Grid. The client had no documentation or source code.

Our initial contact with the client was in 2010 to effect a repair to the plant which had been shut down due to a fault. We have supported the client ever since.

Our most recent project was to upload and reverse engineer the software from their PCD's and then convert it back to a meaningful format (Ladder/Fupla). Because of the dangers involved with such a process, we created a model simulating the functions to include a pair of Variable Frequency Drives(VFD) linked to a pair of compressors feeding into a small air reservoir.

The control system has a Saia PCD2.M150 with 196 I/O and uses PID to control the VFD's. We were able to maintain the required reservoir pressure to 210mbar regardless of the exhaust air loss. This was demonstrated to the client, initially via Skype and after approval, the first phase (Plant A) was installed in February 2016 and the final stage (Plant B) installed in June the same year.