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All-round benefits of SafetyBUS p demonstrated

A Safety Network International eV product story

Edited by the Engineeringtalk editorial team Sep 6, 2005

Soudronic Automotives (Switzerland), a specialist welder of tailored blamks, has adopted SafetyBUS p and programmable safety systems with great success.

When it comes to welding tailored blanks, Soudronic Automotives (Switzerland) is one of the world's leading specialists.

Using complex laser machines, different grades, forms and thicknesses of plate can be welded together.

Soudronic uses a Pilz Programmable Safety System (PSS, or 'safety PLC') with decentralised I/O modules, all linked via a SafetyBUS p fieldbus, to ensure safety, versatility and high availability.

The plates are welded and, during various subsequent treatment processes such as cleaning, oiling and beading to customer's request, prepared for the follow-up processes and transported to the unload stations.

The individual work areas are combined into safety cells and separately safeguarded.

Numerous hazards are present in the working area, such as the YAG lasers, hydraulic presses, and sharp-edged plates being handled by robots, haulways and pallet cars.

During the normal production process there are no personnel present in the hazardous areas, with interlocks used on access points.

However, during start-up, maintenance or if special programs with manual assembly are called for, the situation is very different.

It is possible that individual safety issues must be addressed, for example, to allow parts to be inserted manually for short production runs, or to perform repairs.

Furthermore, upgrading or refitting the plant with additional functional modules can make it necessary to temporarily shut down part of the plant.

All such cases have the following in common.

Manufacturing in the unaffected part of the plant should not be interrupted and it conditions must not arise that could endanger personnel.

Additionally, by cross-linking the safety control system with the standard control and HMI, the condition of each safety component and each safety circuit can be monitored and faults diagnosed.

This saves considerable time for the operator and also for the maintenance process.

By judicious use of SafetyBUS p and suitable plant zoning, it is possible to segment the safety systems within plant into a maximum of four safety cells with up to: 24 safety potentials; 108 emergency stop buttons; 32 access points; 12 muting safety light curtains; 12 bypass light curtains; 8 manual loading stations (inclusive escape doors); and 6 connecting doors.

All of this is supervised using a Pilz PSS and SafetyBUS p fieldbus with up to 38 safe decentralized I/O modules connected.

These decentralized I/O modules process the safety-related signals.

In the past years more than 30 plants have been commissioned.

The following empirical values were collected: expenditure for the software parameterisation per plant is < 0.5 day; material costs are constant; costs and start-up time much lower; errors can be located and repaired with SafetyBUS p within the shortest possible time; the control is firmly integrated into the plant and accepted by operators; security for commissioning engineers and projects managers is no longer an issue; additional components can simply be integrated later on; and the SafetyBUS p safety control is accepted by all customers.

The decision to use a SafetyBUS p safety system has therefore been shown to be favourable in all respects.