AB Technology has used Mitsubishi Inverters, PLCs and MX SCADA to automate their food additive manufacturing process which until recently, was entirely manually controlled.

AB Technology is part of Abitec Group and manufactures food grade emulsifiers for use in a wide range of bread products made by the group. The current process plant in Northampton was built around 10 years ago and until recently, had even such basic operations as opening and closing valves under manual control. Production rates and product quality varied across the four operator shifts and there was always the possibility of product waste and plant shut down through operator error. A simple mistake resulting in a product batch being routed incorrectly could result in a plant shut down of 4 hours or more.

The first stage of automation came in 1995 when a Mitsubishi FX PLC was installed on a part of the esterification plant where fats are first mixed in a loading vessel, pumped to a reaction vessel, heated and then cooled before transfer to the distillation plant. A PLC was installed to control interlocks on the pumps and valves and for the first time operators had a graphical plant interface in the form of a Mitsubishi MAC 90 HMI.

The success of this first step and the ease of installation and operation of the Mitsubishi equipment encouraged Martin Rogac and Dave Sampson at AS Technology to look to other parts of the process that could be automated and to consider installation of a SCADA system to give a more detailed view of the plant.

After an initial training course at Mitsubishi's purpose built Customer Technology Centre in Hatfield, Martin Rogac produced his own SCADA mimics in house. According to Dave Sampson, AB technology needed some support from Mitsubishi and Pneumatic Lines, a Mitsubishi Key Partner company for the initial set up but since then have been largely independent. "The Mitsubishi equipment has proved very easy to integrate" says Dave Sampson, "We have A500 inverters as well as the FX and FX2N PLCs and they have really been 'plug and play'. They are also very reliable so once installed, you can just forget them."

AB Technology now have around 20 FX and FX2N PLCs on site controlling a wide range of activities including weighing of ingredients using the PID function on the FX2N to control feed rates. The production process requires a constant supply of water so AB Technology have set up their own water storage tanks, also controlled by PLOs to safeguard against supply failure and are currently working on a project to use the FX2N to control condensate recycling in order to cut down on waste water.

The new automated control has also allowed AB Technology to achieve cost savings by changing parts of their process. For example, product was previously loaded cold into the reactor vessel, heated by gas-powered, thermal oil boilers to 230 0C then run through a heat exchanger to cool it to the required temperature for pumping on to the distillation plant. The hot material is now piped past the mixer vessel such that the heat from the cooling material is used to preheat the next batch before it goes to the reactor vessel. This has resulted in significant cost savings on fuel.

The complete plant overview afforded by the MX SCADA system has allowed AB Technology to compare activity across all shifts and copy work patterns for maximum efficiency. "Production increased overnight" says Dave Sampson. The new system has proved very popular with operators who can see at a glance the stage that each batch has reached. Dave Sampson and Martin Rogac are now working on bringing real time plant information to the management offices via SCADA nodes on an Ethernet network that will address a server PC holding the PLC polling records.

Mitsubishi Electric Europe, through its Automation Systems business, provides automation and information systems to manufacturing and process industries. A part of the $36 billion Mitsubishi Electric Corporation, and one of the largest players in the industrial automation market, the business unit has European sales of $200M.