When we think of industrial machine safety, we typically think of guarding as simply a matter of physically blocking access to a dangerous area such as a pinch point, control panel, or running machine. But this is the age of IIoT, and shop floor safety and productivity are interested in more than keeping peoples fingers out of paces where they shouldn’t go.
In this video, Thomas Kolleck, sensor technology engineer at Turck, takes us through a show floor demonstration of the hybrid safety block.
“We saw a need for combining safety I/O with standard I/O. People weren’t using a lot of safety I/O. In customer’s installations, it was typical to see a safety block with 8 safety ports, with only two or three of the safety ports in use. Beside that block, a standard I/O block would be using two or three standard ports. We thought, why not combine the two blocks to save room on the machine?” said Kolleck.
The SIL 3 rated safety device can drives outputs and receive inputs with two safety input ports and two safety I/O ports.
In the demo, an interlock device and safety emergency shutoff are connected to the system. In the event of an E-stop, the block signals the safety controller that the door needs to be unlocked, allowing entry. The motor is stopped, but there is still power to the encoder and other devices on the safe side, with data that need to feed back into the I/O. When the personnel are finished in the cell, they close the door, reset the switch, and the machine is ready to be restarted.
“What really makes it safe is the redundancy and safety circuit inside the safety inputs,” said Kolleck. “If the E-stop dropped off the network, the block automatically unlocks the area and shuts all the safety outputs down so you can access the area without any harm to any equipment or personnel.”
Systems like this are redundant, safe and efficient in the sense that the equipment does not need to be completely shut down, and the system is protected from failure of the wiring or E-stop switch, for example.
Applications of this system include stamping, automotive, and robotics--anywhere with a limited access area. You can plug a light curtain directly into the safety I/O block to restrict access and make sure things shut off when people get to close to danger.
For more on industrial safety, check out VIDEO: Optimizing Efficiency and Safety with Intelligent Industrial Robot Cells.