lntersurgical, Europe's leading manufacturer and supplier of single use respiratory care products for hospital use, is using PLCs from Mitsubishi Electric on a newly developed test machine for their flexible breathing systems. The lntersurgical range of products is used in anaesthesia, conscious care, critical care and emergency care for the delivery of gas, aerosols and anaesthetics to the lungs. In June 1998 all medical products supplied within Europe will need to be CE marked indicating that the product has been designed and manufactured under controlled conditions and that the manufacturer claims that they are safe and effective. The newly developed test bed forms part of the process of ensuring that the lntersurgical range meets this requirement by individually testing for leaks and occlusions across the entire range of more than 6000 product variations. A Mitsubishi FX64 PLC controls air flow and pressure to a variety of nozzles and hose fittings to suit the wide product range with measurement via the PLC's analogue to digital conversion function.

The test parameters for each hose are programmed by a security cleared supervisor and loaded to the PLC via a 16 colour Mitsubishi E700 HMI (Human Machine Interface). To test a system the operator enters the part number of the current product for test on the HMI keypad and a diagram of the product appears on screen. The diagram shows where each part of the system should be fitted on the test bed with number references. At the same time the appropriate numbered connections on the test bed are extended by pneumatic cylinders for easy identification and fitting. To test a different product the operator has only to enter a new part number so set up for batches is quick and simple and operator training is minimised. Information is displayed in both text and graphical format with clear pass/fail information on screen and any product failures trigger alarms which are stored with measured values for later printing and analysis.

The engineering team at lntersurgical develop and build their own assembly and test equipment in house. They have ongoing support both from Mitsubishi Electric and Mitsubishi Key Partner, Pneumatic Lines, including training courses in PLC programming and in SCADA systems at Mitsubishi's Hatfield site. As part of a continuing upgrade programme, existing assembly equipment is being converted to PLC control to allow modification to suit lntersurgical's developing needs. Mitsubishi PLCs have been specified as a company standard because of their flexibility and reliability. According to Luke Bedggood, Process Development Engineer at Intersurgical, "the Mitsubishi PLCs had the flexibility to allow us to achieve our aims. We need to increase the level of automation in our production and test areas to support the company's significant growth."

Business benefits to lntersurgical from the current level of automation have included access to more detailed management information, lower reject rates and higher output. Fewer operators are needed for each process so experienced operators are freed up for other jobs as the company grows. This is a particular benefit as lntersurgical operates in an area of high employment where recruitment and training can be difficult and costly. Output from one assembly and test area since the Mitsubishi PLCs were installed has shown a measured improvement from 1,000 items per 8 hour, 4 person shift to 2,500 for the same period. RS485 cable installation is now underway in preparation for a complete Mitsubishi SCADA system for the production and test facilities factory wide.

Mitsubishi Electric Europe, through its Industrial 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.

In the UK, automation systems solutions are delivered through a network of key distributors and Systems Integration Partners, selected, trained and closely monitored by Mitsubishi. Market leading products include Fx small PLCs, A Series modular PLCs, AC Drives, Servo Positioning Systems and Q Series Process Control Systems. A comprehensive array of supervisory and control software, industrial Human Machine Interfaces and Low Voltage Switchgear completes the range.