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Gary Provis from Siemens Industry Automation highlights some of the benefits that can be achieved in process operations through use of certain diagnostics tools now readily available.

There is a requirement for all companies to satisfy pressures to increase operational efficiency, reduce costs and maintain production levels, particularly in an automation environment.

With onsite maintenance and engineering manpower also under scrutiny as costs continue to be examined, diagnostics tools can aid fault-finding and rectification.

Human machine interface (HMI) devices report faults in automation systems either automatically as system diagnostics (with no configuration and no cost implication in SIMATIC solutions) or via manual intervention.

However, with an estimated 80 per cent of faults during any operation process being related and the fact that diagnostics are plant-specific and cannot be integrated into the controller (resulting in programming needs and increased cost), the role of diagnostic tools in alleviating ever-spiralling overheads and keeping plants running has never been more vital.

Conventionally, process diagnostic functions are programmed separately from the actual control programme and appropriate error messages, alerting operators to faults, must be displayed on the display equipment.

The associated programme code work can easily be as extensive – and expensive – as the overall control functions themselves and if the control programme is modified in any way this also results in the monitoring functions having to be reprogrammed.

With management scrutiny on expenditure at all times the potential outlay exposure in the process area can be considerably reduced using a range of simple diagnostics tools.

The tools when specified offer a number of clear advantages for implementation and operation alike, such as simplified configuration and automatic change management.

Here process diagnostic tools through SIMATIC are configured in one step when the automation control solution is programmed.

Variables are monitored and marked, the error state defined and a comment assigned to it.

Likewise any monitoring functions are automatically updated when the control functions are modified.

Diagnostic tools can also help in the key areas of troubleshooting and preventative work, and pre-emptive fault finding can be a real asset in a process-operating environment, in which maintenance budgets must be kept under control.

When a fault occurs, the implementation of a user-friendly criteria analysis enables the precise criteria in the network or the logical operation that resulted in the error to be displayed.

Such a criteria analysis does not require a programming device as it is performed on the HMI device, which accelerates error detection and rectification drastically.

Likewise in the area of preventive maintenance, disturbances in the process sequence can be detected at an early stage and interpreted by operational personnel.

This means that faults are prevented and instances such as tool wearing – which is indicated by increasing frictional forces – are quickly identified and rectified before a small issue becomes a major problem.

Process diagnostics tools can monitor such frictional forces and action taken to rectify the situation, usually at a much lower cost.

Remote-control machines and plants are increasingly operated in places that are far removed geographically from the place of manufacture but plant constructors must nonetheless be able to provide support in the event of a fault.

Here, developments in remote maintenance and remote link via services such as telephone-cable-based TeleService can make significant contributions to the smooth running of process plants through remote diagnosis, value setting and data transmission from any location back to a central operator point.

Through such implementation service-call occurrences can be cut drastically and resulting travel and personnel costs slashed.

For remote maintenance a designated operator can simply dial into a remote plant by telephone and read status information or correct the user programme remotely.

Three types of remote connection are achievable, including: remote connection to a plant initiated by a programming device or PC for tasks such as transmitting recipes to a remote plant or transmitting process files for analysis or processing at a central office; remote connection to a PG or PC initiated by the plant; or remote connection between two plants for exchanging process data.

The remote and user-friendly capability lies in the ability to send text messages from plant to a mobile phone or to a provider for onward communication via fax or e-mail.

It is clear that there is a constant need to work smarter.

Technology available through some of the diagnostic tools outlined here help in this objective, saving time and money in many cases of monitoring, fault-finding, preventative maintenance strategies and remote control, all of which are now easily within the reach of plant operation.

Siemens Automation and Drives

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