IEN: What are the major machine and worker safety issues facing industry? How can they be addressed?
O''Laughlin: National consensus standards, such as ANSI/RIA R15.06-1999, establish expectations for the use of risk assessment and the implementation of machine safeguards for both the builder and the customer. The builder of industrial machines may now be expected to offer the customer a risk assessment for the machine that indicates what hazards exist on the equipment the builder is supplying, what safeguards have already been implemented, and what hazards are left to the end customer to mitigate.
In the past few years, a trend has developed in North America to utilize harmonized safety standards from throughout the world. Examples include ANSI/UL 61496-1, -2 and IEC 61508. These standards affect the manufacture and design of a variety of safety components ranging from safety-rated programmable logic controllers (safety PLCs) to safety light curtains and safety laser scanners. As the implementation of these devices continues to increase in North America, application-oriented standards may be the next group of standards that will be harmonized globally.
IEN: Where are strides being made: In ease of integration? Flexibility and scalability? Safety management? Personal injury prevention? Risk management? Safety design? Emergency response? Hazard controls? Elsewhere?
O''Laughlin: With the advent of safety networks, there are enormous strides in the areas of flexibility, scalability, and safety management. The key driver of design flexibility with safety networks is a reduction in the hardwiring of safety controls (see figure below). With the replacement of multiple wires with a network wire, changes and reconfigurations with future system expansions are greatly simplified, thereby providing a highly scalable system.
In addition, safety networks such as DeviceNet Safety and PROFIsafe offer flexibility and scalability because current standard DeviceNet and PROFIBUS users can implement a safety system by simply adding DeviceNet Safety or PROFIsafe devices to the existing fieldbus. Existing standard networks can therefore be expanded through a seamless, multi-link architecture to include standard and safety controls with unlimited numbers of devices. Because safety networks such as DeviceNet Safety and PROFIsafe can also be interconnected to a high-speed Ethernet backbone (e.g. PROFInet and EtherNet/IP), the safety and standard controls can be further integrated. Without expensive safety-specific hardware such as gateways and routers, a seamless transfer of data between the plant floor and the higher-level enterprise can occur.
IEN: What innovations are in store for users in machine safety, protective technology, ergonomic design, safety equipment and systems, environmental equipment, software, training, and other areas?
O''Laughlin: Until recently, fieldbus networks have been limited to non-safety applications due to hard-wire and hardware requirements for safety systems. Recent modifications to standards now allow use of safety-rated fieldbus networks for industrial machines, robots, and other equipment. Safe fieldbus networks provide time and cost savings opportunities that builders using standard PLC systems have benefited from for years.
Safety standards, such as IEC 61508, NFPA 79, and ANSI/RIA R15.06-1999 define the requirements for the design and implementation of safety-rated programmable systems. IEC 61508 addresses functional safety in programmable electronic systems, allowing systems to enter a predetermined safe state through safety-rated networked devices. Underwriter''s Laboratories (UL) has developed a new test category (NRGF) for the purpose of testing programmable safety systems-based hardware.
Safety bus networks such PROFIsafe and AS-I Safety at Work, as well as the soon-to-be-introduced DeviceNet Safety, are quickly gaining ground, and are offshoots of the standard bus networks PROFIBUS, AS-I, and DeviceNet. Builders and customers benefit in the following areas:
Reduced Wiring Efforts
- Reduction in the number of components required
- Locating RIO closer to sensors and actuators
- Making replacement of modules simpler without interrupting other I/O
- Simpler assembly of subsystems
Machine Availability
- Faster debugging capability
- Improved diagnostic functions
- Lower Mean Time To Repair (MTTR)
- Remote Maintenance and Diagnostics
- Reduced time to restart
Improved Technology
- Changeover from relay-based solutions to control system solutions
- Increased automation capability
- User mode functionality
- Provides easier expansion capability and component reusability
Media Independent Protocol / Multi-Vendor Solutions
- Increased flexibility through user-selectable component choices
- Protects hardware investment now and in the future
- Reduction of acquisition costs due to competition
- Reduction of engineering costs through commonality of parts
SICK additionally sees a technology trend in providing integration technology and products to integrate all relevant safety sensors, actuators, and operating devices into safety applications.
IEN: What are the R & D hotspots, and which R & D areas are closest to commercialization?
O''Laughlin: Currently, SICK is a member of a consortium that is developing the definition for DeviceNet Safety and the first components that will operate on the DeviceNet Safety fieldbus network. The first components from the consortium will be released later this year with a complete range of components expected to be available in early 2005.
IEN: Will the web and/or wireless play greater roles in safety? If so, how?
O''Laughlin: The web is expected to play an increased role in allowing users to obtain diagnostic information from safety-rated systems. However, safety-rated functionality requires that the system be safety rated for the purpose of safety-rated control. Since this does not exist today, web-based or wireless-based systems cannot be utilized for safety-rated control functionality.
IEN: To what extent can companies integrate safety systems into other industrial systems?
O''Laughlin: With the advent and acceptance of safety-rated fieldbus protocols, companies now have the ability to tightly integrate safety systems with standard control system architectures. The safety devices that are utilized must still be controlled by the safety-rated parts of the system. However, the safety-rated systems can coexist on the same network wire -- reducing cost and promoting full diagnostic information availability.