by Rene Makalintal
Lead Project Engineer
In industrial processes, there is no room for safety errors. Safety incidents have serious consequences: They are expensive, interrupt production and availability — and have an irreversible impact on the people who are part of the process.
However, industrial producers have traditionally separated process controls and machine safety systems. A new push to integrate the two overcomes challenges that have been keeping safety controls apart.
A history of separation
Integration of process and safety systems has been a matter of debate since the 1980s. At that time, process control systems didn’t have the functionality to control safety systems as well.
In fact, the general consensus was that the two systems shouldn’t be integrated because safety systems must be able to override process automation to ensure effective protection for personnel. However, today’s systems are significantly more sophisticated, and process engineers are realizing there are good reasons for allowing the safety system and process controls to share some information.
What does an integrated system look like?
In the Automation World article “Process Automation: Making the Case for Integrated Safety,” author Aaron Hand explains that in any industrial process, safety measures are applied in layers:
- Process control system
- Safety instrumented system
- Physical and community safety procedures
The layers ensure that if one measure fails, another layer will provide the necessary protection. However, even though each layer must operate independent of the others, they can also share a certain amount of information that will allow coordination of safety measure across all the layers.
Industrial controls provider Omron notes that integration of process and safety controls simplifies automation and offers numerous benefits.
- Reduced automation complexity.
- A standard interface can link and manage all equipment and components.
- Reduced safety measure reaction time.
- Shortened restart time after a safety trigger.
- Faster programming, maintenance, and upgrades.
- Systems can be more easily scaled to meet changing production needs.
In addition, integrated diagnostics allow for more effective troubleshooting and greater accuracy in processes.
Likewise, integration of process and safety controls also presents challenges. Without careful and expert design, integration can increase the risk of common-cause failures and the chance that a process control system failure might affect the safety controls. Management of the combined systems can also present challenges.
A good overall industrial controls design ensures safety stops happen when they need to — and don’t interrupt operations when they don’t need to. Be sure you work with a highly qualified system engineering team to create the delicate balance that an integrated system requires.