Simple Scada job expands to plantwide control

A modest project to automate a compressor house has been expanded to embrace the whole of Yorkshire Fittings' Leeds factory.

A modest project to automate a compressor house has been expanded to embrace the whole of Yorkshire Fittings' Leeds factory.

The initial project was based on the installation of a Mitsubishi Electric MX32 Scada program to monitor the performance of a bank of compressors.

The main idea was to optimise energy usage, but it also became possible to log detailed operational data for productivity analysis allowing a move to predictive maintenance.

The efficiency gains achieved with the compressors were almost immediate and, because of the data logging, full management reports were produced.

These impressed the directors so much that they were soon asking the electrical engineers if the control network could be extended into adjacent areas of the plant.

There was some scope for doing this and improved productivity was quickly noted.

It was not long before the idea of running the network across the entire site was taking root and Mitsubishi's Tony Dean was asked to join a development team.

"Yorkshire Fittings engineers had worked out several potential schemes for how best to proceed, bearing in mind that they would not want to disrupt production, knew what management information they wanted to produce and had some ideas on systems architecture", says Dean.

"I asked if there was likely to be further developments later and got the great answer that nothing was ruled out so long and it would improve productivity and/or quality".

"I then suggested that to do real justice to the site and allow effectively infinite scope for future expansion that we upgrade the Scada to our MX4 package".

MX4 is Mitsubishi's latest suite of production management software.

It is a process visualisation package which can be configured for just about any industrial automation application - from single machines to entire remote-controlled plants.

It offers the prospect of "zero downtime" through duplex I/O and dual redundancy connections to ensure that no data is lost in the event of a computer failure.

Yorkshire Fittings saw this as critically important, as production downtime is something its market cannot tolerate.

Dean explains that MX4 grows with the customers' applications.

"Its modularity means that installed systems can easily be adapted and extended as needs develop over time".

"MX4 is available in a variety of configurations, from the simple, stand-alone human-machine interface version MX4 HMI to the complete process control software package MX4 Scada.

In addition to this MX4 also includes a powerful development environment, with simulation functions for no-risk development and testing".

Dean, along with colleagues from Mitsubishi, undertook an audit of all the existing control systems running different parts of the plant and worked out an efficient way of knitting these all together into one coherent system with MX4 at its heart.

Many of the machines were already controlled by Mitsubishi PLCs (programmable logic controllers), small FX units for simple sequencing logic on individual machines and A- and Q- series controllers for more complex control of larger islands of automation.

Additionally Yorkshire Fittings had invested in Mitsubishi E900 HMIs (human machine interfaces) to provide local process visualisation and management.

With the hardware in place the next objective was to connect it all up into a single plant-wide network.

CC-Link was chosen as the shop floor protocol for communicating between field devices and production machinery.

This was relatively simple to implement because the A- and Q-series PLCs have an optional plug-in CC-Link card.

The local networks were then connected to the high level servers providing enterprise management capabilities via an Ethernet network.

In fact the decision was made to design-in two servers, a primary and a standby so that the system would be virtually bombproof against downtime.

Tony Lepecha, Yorkshire Fittings Electrical Engineer, explains the thinking behind this: "We're a 24x7 operation, supplying to a demanding Europe-wide industry with tight margins, no stockholding and fierce competition from other manufacturers".

"If we lose production, the problem is magnified at each step along the logistics chain to the final customer".

"Continuous production reliability is our number one objective, only after that is secured can we look at energy efficiency, increased productivity etc".

Lepecha says that all the mass production lines at Yorkshire Fittings are now on the MX4 network.

The next project will be to bring the batch production products on-stream and he is also looking at switching to wireless Ethernet.

"On a site as big as ours, the potential savings in cable is enormous", he says.

"The success of the MX4 installation has given us confidence in emerging technologies such as wireless communications and their ability to improve our overall productivity".

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