PC provides CNC and PLC functionality

Reliability, versatility and ease-of-use are among the principal reasons why a missile manufacturer chose a PC-based control system for a machine, which winds Kevlar onto aluminium forms.

Reliability, versatility and ease-of-use are among the principal reasons why Egbert Systems has chosen a PC-based control system using software and hardware supplied by Hayes Control Systems to automate one of the key processes involved in the manufacture of armoured anti-aircraft missiles.

The new system was developed by Egbert Systems to replace the existing control equipment on a machine which winds Kevlar onto aluminium forms for use in the missiles.

"We evaluated many alternative approaches," said Martin Wiltshire, of Egbert Systems, "but this project required CNC control with a custom front end.

No conventional CNC system or programmable controller was able to meet the requirements at a reasonable cost.

However, the Beckhoff TwinCAT software package from Hayes, which runs on an ordinary PC, provides both CNC and PLC functionality, and gave us the flexibility we needed." The central component of the new installation is a rack-mounted PC, running Windows NT 4.0.

The TwinCAT-based control system is implemented as three servers and an application program, all running on this single machine.

One of the servers services the input/output systems, another provides the PLC functions, and the third handles the requirements of the VDU-based operator interface.

The application programme for the operator interface is written in Visual Basic 6.0.

To link the control system to machine-mounted devices, Egbert Systems uses Beckhoff Lightbus products which offer an inexpensive, yet flexible, approach to implementing fibre-optic fieldbus systems.

"The Beckhoff products, for which Hayes Control Systems is the sole UK supplier, were very easy to use," said Egbert's Martin Wiltshire, "and the technical support given by Hayes is outstanding.

Commissioning went very smoothly and, in particular, was helped by the special "oscilloscope" function which is built into TwinCAT.

This was an important aid to setting up the tensioning system for the Kevlar." "These benefits," continued Wiltshire, "combined with the very competitive pricing of both the hardware and software from Hayes, mean that we will definitely be basing future designs on Beckhoff products." For the end user, the new control system offers improved efficiency and reliability, along with the capacity to cope easily and inexpensively with future modifications and extensions.

It is much more compact than the system it replaces, and much easier to maintain.

Hayes Control Systems is the leading UK expert in the design and supply of complete automation solutions based on open-architecture PC technology.

The company is the exclusive UK distributor for Beckhoff in Germany, whose products include fieldbus-independent input/output systems, industrial PCs, and soft programmable controllers which use standard PC hardware, and which can also provide sophisticated motion control functions.

In all of its product areas, Hayes Control Systems champions an open-systems approach, which avoids the technical limitations, high costs and restricted availability associated with proprietary equipment.

(This was Manufacturingtalk's Top Story on 5 March 2002).

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