An introduction to CC-Link Safety
CC-Link Safety is a network with high reliability in data transmission suitable for use in safety applications that require compliance with IEC61508 SIL3 and EN954-1/ISO13849-1 Category 4. CC-Link Safety is compatible with standard CC-Link. It allows the use of existing investments in network cable, other compatible products, and existing engineering effort. Safety devices and non-safety devices can reside on the same network. CC-Link Safety will detect communication failures such as unexpected delay of communication or erroneous data that may cause malfunction of the emergency stop operation. This fail-safe function will bring machinery into a safe condition quickly if a communication failure is detected. Safety master station maintains error and failure histories of the safety remote stations.
IEC61508 SIL3 requires less than 10-7of undetected communication failure rate. CC-Link Safety meets that requirement and will detect communication failures that may cause malfunction of the emergency stop operation. This fail-safe function will bring machinery into a safe condition quickly if a communication failure is detected. This is accomplished by adding a safety function layer on the upper level layer of CC-Link protocol that detects each transmission error. Information for the safety function layer includes a “running number” to specify message order and CRC32 to detect a safety data error.