Posted to Technical on Saturday, April 30, 2016 Share:

The benefits of active safety for machine builders and end users

Murrelektronik explains how the use of active safety products, connected to a PLC via a fieldbus network, offers advantages for machine builders, system integrators and end users.

Murrelektronik is well known as a supplier of passive safety products. Passively safe fieldbus modules like the MVK Metal, Cube67 and MASI, combined with MIRO safety relays, create safe installations. If necessary, the module's outputs are switched off so the affected machine parts are also safely shut off. This simple approach means concepts and standards can be maintained.

With the MVK Metal Safety, Murrelektronik also provides active safety technology. This rugged fieldbus module provides safe inputs and outputs in combination with a safe control (safety PLC). Using the Profinet/Profisafe fieldbus protocol ensures that safety-related data is transferred reliably. The MVK Metal Safety is part of a complete system that fulfils high safety standards.

Murrelektronik's new fieldbus modules enable installations with Safety Integrity Level 3 (SIL 3) according to IEC 61508 and IEC 62061, and Performance Level E (PL e) according to EN ISO 13849-1.

The fully potted MVK Metal Safety modules (pictured right) are suitable for applications in harsh industrial environments thanks to IP67 protection and high resistance to media and vibrations. Moreover, they feature comprehensive diagnostic options.

Typical applications include: connecting emergency stop circuits, guard doors, safety mats, light barriers and two-hand control devices, as well as applications in machine tools and machining centres, in forming and sheet metal working equipment, in foundry plants and forges, and in cutting and welding units.

More safe outputs

Now it is easy to increase the number of safe outputs within a system by using a combination of Murrelektronik's Cube67 fieldbus modules and the MVK Metal Safety fieldbus module. This saves cabinet space because safety relays are no longer necessary.

If there is an emergency on the shop floor - for example, a guard door has been opened or a light curtain activated - outputs have to be switched off immediately. Combining safety relays with K3 fieldbus modules is an easy method to achieve safe outputs. This is practical for smaller applications with basic requirements.

In order to design an installation based on Cube67 modules (pictured right) that meets the highest safety requirements, a combination of the compact and safe MVK Metal Safety fieldbus module with Cube67 K3 modules is an excellent option. With the MVK Metal Safety outputs - controlled by a Profinet/Profisafe controller - up to 12 safe outputs can be created on the K3 module. They are split into two safety circuits, each with three ports that have dual functions. This multiplies the number of safe outputs and is a simple and efficient method for increasing the competitiveness of machines and systems.

To complement both active and passive safety systems, Murrelektronik has just launched a range of emergency stop pushbuttons utilising industry-standard M12 connections. These, and the other products mentioned above, are available from the Murrelektronik online shop.