​Advancements in Safety Devices for Manufacturing Automation

In the realm of manufacturing automation, prioritizing safety remains crucial, especially when human interaction with equipment is involved. Over the years, safety devices have undergone significant changes, evolving from basic e-stops and door switches to sophisticated safety relays with dual-redundant circuits. This progress in safety technology has paved the way for deploying a wide variety of automation systems in manufacturing environments, including collaborative robots (cobots). Let's explore the key safety components and approaches employed by manufacturing safety engineers to ensure seamless human-machine interaction.

Sensing the Danger

The first step in creating a safe manufacturing environment is to accurately sense the proximity of humans to the operational area of the machines. Collaborative robots, designed for close interaction with humans, utilize technologies such as joint resistance sensing, pressure-sensitive safety skin, and loosely fit guards. These features allow the robot to detect obstacles or contact with a person, prompting the robot to slow down, change direction, or stop immediately to prevent accidents.

For larger and faster robots with higher payload capacities, additional safety measures, such as light curtains and area scanners, are deployed to extend the non-collaborative operating envelope. If a person or object breaches this area, the robot automatically switches to collaborative mode, employing all available safety sensors for a safer interaction.

Stopping the Action

In case of a safety-triggered event, various safe motion features come into play to stop or reduce machine motion. Safe torque off (STO) is a fundamental motion safety function that completely disables the output stage of the drive, rendering it torque-free. Safe stop and safe stop emergency are other responses to safety situations, involving controlled motor ramp-down to zero speed and deploying either safe stop or safe torque off based on the controlled device.

Additionally, safety limited speed (SLS) and safety maximum speed (SMS) limit the robot's motion to specific slow speeds or speeds less than full speed, respectively, for enhanced safety during potential risks.

Utilizing Safety Processors

In more complex machines, employing dedicated safety processors becomes essential to ensure proven, reliable, and repeatable safety responses. Unlike safety relays, safety processors can add logic to create groups of safety devices and associated safety outputs. Each safety input is individually connected to the safety controller, which monitors the dual channels of each device and communicates status to the main programmable controller without requiring physical wiring.

Safety controllers are typically programmed pictorially using gate logic and offer built-in features based on the type of connected devices. Their independence from the main machine-control algorithm ensures faster decision-making and enhances overall system safety.

Advancements in safety devices and technology have revolutionized manufacturing automation, allowing for the deployment of collaborative robots and reducing the need for hard-guarding. With sophisticated safety relays, processors, and a diverse range of safety devices, manufacturing safety engineers can create safer environments, enabling humans and machines to interact seamlessly within smaller, yet more secure, operating envelopes. Embracing these cutting-edge safety measures enhances manufacturing safety and efficiency, safeguarding both workers and equipment in the automation era. Contact us today for an introduction to the latest in safety technology for industrial manufacturing environments.