Technology is advancing at an ever increasing rate. Safety is no exception to the advances of technology. In the not too distant past, safety devices on a machine only included mechanical guards, properly sized and selected components, and emergency stops that when pressed would cause the machine to stop moving. Fast forward to today& there is a whole new set of advances in safety devices and practices. The desire to create circuits that continued to function in the event of a failure brought forth the concept of Control Reliable and safety relays.
Advances to safety including lock out/tag out, and NFPA 70E introduced other new processes and Personal Protective Equipment to make working in and around machinery safer. But theres more, much more!
Risk Assessment is becoming a common tool to proactively determine what aspects of the system or machine need safety attention by rating the severity, probability, and avoidance of hazards. Items like Safety PLCs and Safety controllers allow the safety functions to be programmed thus eliminating extensive physical interconnection or interlocking for safety circuits. Safety networks allow the safety devices to coexist on the same networks as the rest of the system I/O eliminating a substantial amount of dedicated wiring. Safety Torque Off in motor drives integrates the contactor functionality into the drive and eliminates the need for external devices for e-stop. All of these advancements are designed to reduce the cost of implementing the safety system while increasing functionality.
Continuing to look into the future, vision-based safety sensors are being brought to market to replace safety mats and fences in work cells. Research and advances in safety detection and machine control might allow a person to safely work side by side with a robot or other equipment within a work cell someday and provide enhancements in productivity.
Lastly, all of the above advances in safety technology come with responsibility:
- Do your homework. Learn about the technology and make sure it has been tested, certified, and meets current safety standards before implementing it for safety in production. Many vendors of components like Rockwell, Sick, Omron/STI, and Euchner have free safety booklets available for download from their websites which describe much of the above in more detail.
- Select vendors and integrators that have a good understanding of the technology and can help educate you on the new technology.
- Educate the operators, maintenance persons, and anyone else interacting with the equipment.
- Develop and follow good procedures for password protection, version control, and component replacement. Insuring that the correct program or configuration has been downloaded when a component is replaced and controlling changes to programmed safety devices is important.
- Develop a validation procedure for testing changes to safety programs and configuration.
- Provide appropriate preventive / predictive maintenance for the safety components. Even though many of the new components are designed to fail in a safe manner it doesn't eliminate the need to check them on a regular basis.
