Thursday, July 17, 2008

Safety in Automation (Part 3 of 3) Safety Switches

Safety Switch Technology With Sensaguard
Safety in Automation: New Products

The new Allen-Bradley SensaGuard family of RFID-coded, non-contact switches from Rockwell Automation includes a high safety rating, flexible design, extended diagnostics and RFID coding, while improving safety and reducing troubleshooting time and machine wiring costs.

The switches are Category 4/SIL 3 rated per EN954-1, TÜV functional safety-approved to IEC61508. Unlike lower rated switches, SensaGuard will shutdown a machine if a failure occurs before there is a demand on the safety device — which improves machine operator safety. They are especially suited for machines where multiple access doors must be monitored up to a Safety Category 4/SIL 3.

Safety Guard Switching Unit

Omron Scientific Technologies has introduced new G9SX-GS safety guard switching units. External outputs enable status indication of two safety input devices. Auxiliary outputs enable monitoring of safety inputs, safety outputs and errors, and detailed LED status indicators provide system diagnostic tools.

Additionally, logical AND connections help facilitate complicated applications in combination with other G9SX series units. Each G9SX-GS unit supports unique auto switching and manual switching functions.

Auto switching ensures safety and productivity in applications with coordinated operations by monitoring a machine or robot, plus the operator, to make certain neither enters the coordinated area at the same time. Manual switching is for applications that require limited machine access for operations such as maintenance and cleaning.

Safe Relays For Process Applications

Phoenix Contact now offers safe relay modules, approved to SIL3/IEC 61508, designed specifically for process applications. Optimized turn-on behavior eliminates high start-up current that a control system might interpret as a short circuit. The safe relays provide two channels of redundant normally open contacts and one normally closed status contact that can switch up to 250V ac/6 A in a 22.5-mm housing.

These compact safety relays are used to electrically isolate field applications from the control system or to adjust the voltage or power. In addition to being used in conjunction with safety-oriented control systems, these relays form an integral part of the safety chain for electrical and electronic applications in process technology and mechanical engineering.

Safe Camera System For 3-D Control and Monitoring

SafetyEYE is a camera system for three-dimensional safety monitoring from Pilz Automation, developed in conjunction with DaimlerChrysler. The system places a customized, three-dimensional protective cocoon around a danger zone with a single system. It is designed to replace a multitude of two-dimensional sensors currently in use today. The system offers functions for control and monitoring and allows detection zones to be configured flexibly and quickly on a PC.

More than just a sensor, SafetyEYE is the basis for a technology that safely detects objects in a three-dimensional zone and alters a robot or a machine's movement to prevent accidents. It is suitable for a wide range of applications from manufacturing operations, to the tire and packaging industries, to high-bay racking systems and automatic car parks. The system can also provide uninterrupted object monitoring and access guarding.

Safe Motion™ Technology With Safety-On-Board

Bosch Rexroth's IndraDrive with Safety-On-Board features Safe Motion™ technology integrated directly in the drive, including the latest international standards for safe stopping and safe motion.

These capabilities are available on a common platform that functions as a servo drive or frequency converter. The system has reaction times up to 400 times faster than conventional solutions that use contactors to produce a safe stop.

Because the Safety-On-Board technology is integrated directly into the drive, motion controllers, regardless of manufacturer, are able to leverage the technology. The drive has enough I/O for the safeguarding logic needed to interface to safety gates, panel switches and interlock switches. The machine builder only needs to learn one safety solution for an application and the machine is pre-certified, so the OEM doesn't have to worry about the safety certification process.

Powerlink Safety

The ACOPOS drive system from B&R Automation uses POWERLINK Safety to enable functions such as safe limited speed directly over the network. Wiring these safety-related signals to the drive is eliminated and the information is collected from its source via safe digital inputs and outputs. It is distributed to corresponding sensors, actuators or drive via the SafeLOGIC central processing unit.

Safety in the drive system comprises the following functions according to Category 3, EN 954-1: uncontrolled and controlled stops, safe stop and safe operation halt, safe limited step measurement and safe limited absolute position, safe limited speed and safe rotational direction. Functions like safe restart inhibit or safe output for the motor holding brake are integral parts of the system.

Safety Relay For Motion In Hazardous Areas

The new Allen-Bradley MSR (Minotaur™ Safety Relay) 57 speed monitoring safety relay from Rockwell Automation is designed to allow personnel to enter hazardous areas while motion is present. The MSR57 will be available later this year.

The device supports numerous input devices such as E-stops and light curtains, allowing switches and interlock switches to stop the motion, put the machine into safe speed and monitor personnel in the hazardous area during safe speed conditions. The MSR57 can be configured and monitored via Drive Explorer or an HMI device. During configuration, the user can set a variety of parameters to specific requirements for their application including type of input devices, door locking and monitoring, enabling switches and a maintenance (safe speed) mode. One example is that the MSR57 can unlock doors automatically when zero speed is detected.

Safety At Work E-Stop Safety Switches

Pepperl+Fuchs has introduced a new family of emergency stop switches with integrated Safety at Work (SaW) functionality. These intelligent switches are powered by the AS-Interface network and offer fast, error-free installation in field or panel-mount applications. Field and panel-mount models are available in high-intensity, wide-angle illuminated versions, as well as non-illuminated versions, to suit any e-stop application requirement.

Illuminated models are lit with a high-intensity LED to eliminate the need for auxiliary power, while reducing the number of required leads to two. For added flexibility, the LED is not activated by the button but is controlled by a PLC, which allows users to solve even the most unusual applications. Non-illuminate e-stops provide safe operation at a lower price point than illuminated models.

Field-mountable versions eliminate all wiring to save time and eliminate the possibility of incorrectly wiring the e-stop switch and feature an M12 connector that works in conjunction with flat-to-round cable adapters to reduce installation time to less than 60 sec.

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