DEVICENET SAFETY PRODUCTS ON SHOW AT DRIVES AND CONTROLS
18 October 2004 - Erwin Sick

DeviceNet Safety is the first implementation of the Common Industrial Protocol (CIP) Safety technology developed jointly by the international DeviceNet vendors association ODVA and ControlNet International. It was launched at the Hanover Fair in March 2004, and provides failsafe communications between devices such as safety I/O blocks, interlock switches, light curtains and safety PLCs.

Global leader in machine safety Sick is among the first vendors to develop products using DeviceNet Safety, and visitors to Drives & Control 2004 saw for the first time its UE 4400 Series IP20 Safety Network Controller and UE 4400 Series IP67/IP20 Remote I/O Bus Nodes.

The UE 4400 controller integrates any combination of safety input and actuator devices into a DeviceNet Safety network, using local or remote safety I/O. This enables the development of coherent and logical machinery safety strategies for applications such as packaging, machine tools and transfer lines.

The controller allows a range of status and fault diagnosis information to be accessed locally or via the DeviceNet network and can handle up to eight safety capable dual channels. Connections are made using plug-in terminal blocks for easy wiring and installation. A large library of approved function blocks is built-in, including logic operations, delay timers, safety gate monitoring and automatic/manual reset.

The UE 4400 Series Remote I/O Bus Nodes are available with either standard IP20 or rugged IP67 enclosures, enabling them to be used within a cabinet or mounted locally close to the machine with no need for additional protection.

The IP67 range links a range of safety sensors and actuators onto a DeviceNet network via easy to use 5-pin M12 mini-connectors. The UE 4420 offers six dual channel safety inputs and two dual channel safety outputs, enabling up to 14 sensors and actuators to be linked to the network using just one field bus address.

The UE 4450 I/O node also offers a Sick Security Data Link (SDL) connection, allowing more sophisticated devices such as Sick light curtains or laser scanners to be integrated into the DeviceNet Safety network.

The IP20 modules use plug-in terminal blocks to connect multiple safety sensors and actuators to the network. Three versions are available: six dual channel inputs only; four dual channel inputs and four dual channel solid state outputs; two dual channel inputs and two dual channel relay outputs.

DeviceNet Safety allows for extreme flexibility when building automation systems which include both control and safety applications based on CIP, as it enables standard and safety devices to operate on the same open network with or without a dedicated safety PLC. It covers safety applications up to Safety Integrity Level 3 (SIL 3) as defined by IEC 61508. SIL 3 is based on a 1 in a 100 million probability of a dangerous failure per hour, and is the highest level required for most industrial applications.

The DeviceNet Safety protocol ensures a high level of integrity, using message redundancy and cross checking to guarantee that safety messages are reliably transmitted from one device and received at another in a predetermined time and with the integrity of the data content maintained.

DeviceNet Safety networks not only provide significant savings in wiring and ease of installation; the network's diagnostic capabilities can also enhance the performance of the manufacturing process. If, for instance, the misalignment of a safety sensor on a robotic arm in a cell located at one end of a plant is detected, the shutdown can be limited to that particular cell. Not having to cut power to an entire area or machine when a safety event occurs translates into improved productivity while maintaining safety levels for operators.

http://www.sick.co.uk

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