A safety relay is an automation device that monitors for potential errors or faults in machinery or plants and works to prevent injury and reduce risk. If an error occurs, the safety relay initiates the appropriate response to reduce the risk and bring the environment back to a safe, acceptable level. Monitoring processes using safety relays protects both the machinery and the employees, prevents potential expensive maintenance and equipment replacement, and reduces risk of human injury.
Example functions include initiating a controlled pause in machinery or equipment to safely stop movement until an obstacle is removed. They can also be used as an emergency stop mechanism, switching off the power to particular machinery or plants until it is safe to resume power and continue.
Safety relays can be single function or multi-function. Single function relays monitor for a specific type of activity and are programmed individually to monitor their respective tasks. Multi-function safety relays can monitor different functions and can be used in place of several single function, individual units to monitor the same number of activities.
The benefits of using multi-function relays include simpler installation and less wiring as fewer individual units are needed. This also makes more economical use of panel space, additionally giving greater flexibility to make changes within the design or panel as fewer units need to be removed or repositioned.
Safety relays are found across many industries where automation is used within a process or for a whole process. Anyone can integrate a safety relay within a circuit to create a safety circuit without any specific training. They are often found in the following control devices: