Interlocks get networked

Most interlocks are either not electrically connected (deliberately so in the case of some mechanical, trapped key interlocks) or are ‘wired at gate’, meaning all electrical connections go via a control PLC and safety relay. This can mean up to 20 wires from each device going to the control panel.

To overcome this scenario, Fortress has developed a number of products that utilise either AS-i industrial networking or PROFIsafe communication technology. Both have major benefits:

• AS-i is an industrial networking platform used in PLC, DCS and PC-based automation systems. It is designed to connect simple field I/O devices in manufacturing or process applications using a single 2-conductor cable. As-i connectivity dramatically reduces the number of wires required, making it possible, for example, to ‘daisy chain’ to up to 62 devices to one control panel.
• PROFIsafe is a safety communication technology for distributed automation. It is designed as a separate layer on top of the fieldbus application layer to reduce the probability of data transmission errors. It allows operators to have just one power and Ethernet cable going from the control panel, allowing devices to be attached in a variety of topologies, depending on requirements.

Fortress in now integrating AS-i and/or PROFIsafe connectivity into the following safety products and over the coming months the following will be available:

• Both the tGard and amGardpro ranges will have AS-i networking
• The amGardpro will also be available with PROFIsafe
• A new stand-alone Non-Contact Switch with an AS-i version; this will also be integrated into the tGard and amGardpro ranges in the future
• An Output Signal Switching Device will be incorporated into the tGard and amGardpro

"Making our products compatible with industrial safety networks is an essential requirement for our customers,” comments Fortress’ managing director Rob Lewis. "With these new product developments being rolled out over the coming few months we’re ensuring we not only meet, but exceed what people expect from us when it comes to industrial networking.”