Industrial machine-safeguarding discussions typically lean toward the latest hazard-mitigating gadgets, instead of exploring new manufacturing processes with built-in safety. Omron commits to integrating safety into core processing to help customers adapt to rapidly evolving factory processes.
“Industrial manufacturing processes demand that machine guarding solutions become adaptable to dynamic manufacturing techniques with diverse functions,” emphasized Mohammad El-Naji, TUV Rheinland functional safety engineer at Omron Automation, who shared his safety knowledge during Omron OPEN 2022, a co-located customer event in Chicago, Cincinnati, Dallas and Detroit.
“As we entered the second and third industrial revolutions, there was still a lot of labor,” said El-Naji. “We needed to produce things at a faster rate, so different zones had products move automatically.” This spawned agencies such as the Occupational Safety and Health Administration (OSHA) to regulate safety in 1971. “As we moved toward automation, the idea was to fence off everything; industrial robots did the manual work, but everything was fenced off,” said El-Naji. “If someone walked in, they’d shut down the entire machine and process.”
Eventually, instead of shutting down the process, the collaboration of humans and machines became a reality as factories moved toward autonomous operation.
Safety components’ evolution has been similar. “In the past you had to de-energize the power going to the drive,” explained El-Naji. “You had your safety relay doing your safety logic. Prior to 2007, the drive could not be used as the final switching device. In 2007, NFPA allowed for the drive to be used as a final switching device. That got rid of our power contactors, and now you can send a signal directly to the drive. But you still had to wire through the relay.” Now, there are drive-based safety functions, such as safe stop 1 (SS1), safe stop 2 (SS2), safety limited speed (SLS) and safety brake control (SBC), among others that are integrated into them.
Prior to 2002, e-stop functions could only be handled through electromechanical components. In 2002, software- and firmware-based controllers could be used in safety-related functions. Safety with standard networking provides more information, and open network protocols, such as industrial Ethernet, are available for third-party communication.
Safety network protocols, such as CIP safety and Safety over EtherCAT, enabled the use of one cable to drive both the safety and standard commands from the advanced safety controller to the drive unit. Multiple devices can be added to that same controller over one safety network with ease. Ultimately, manufacturers are now able to use one controller to perform the standard process and motion/safety control rather than having multiple CPUs and multiple safety devices (relays/contactors).
Enhancements in the Omron NX series safety controllers using Sysmac Studio (programming software) have included unique functionalities. Even if you have no knowledge of programming safety, Sysmac Studio has a feature called Automatic programming that will generate the safety program for you. The Programmer simply states which safety inputs and safety output devices they are using and then fill out a simple cause-and-effect table. The software is then intelligent enough to generate the safety program using TUV qualified safety function blocks. Users will need to validate the program but it will get them at least 80-90% completion.
Sysmac Studio has another unique tool called Simple Automatic Test that can test your program without the need of having any hardware. Using that same truth table used to create your program, it will run a simulation and let you know which safety functions ended up passing and which ones did not. The simple automatic test provides offline testing of program functionality without the need for hardware.
There is also online functional testing. Sysmac offers an embedded tool called the Online Function test that provides a step-by-step guide to validate the safety system online, before starting the machine. It creates a final test report.
Combined with the NA Series HMI, the user has access to safety monitoring features using pre-designed screens that allow monitoring/diagnostics of the safety inputs and outputs, which help in troubleshooting. It is essentially a safety visualization for on-site management.
For electronic sensing or presence sensing, El-Naji noted light curtains, safety mats and scanners. “Operator presence is linked to controlling the machine. New safe presence-sensor technologies and programmable protective operating zones are becoming a necessity in multiple zones that overlap,” he said.
High-speed sharing of information with safety controls is also being developed in a virtual factory floor, creating a digital twin. In addition, more network protocols, such as Safety over IO-Link, are being safety-rated. More safety functions are being added to devices, especially for robots and drives, and mechanical switches. This necessitates network-security enhancements, including firewalls, port forwarding and packet filters. These are put in place to protect the devices from malicious malware.