PROFIsafe
PROFIsafe is a certified profile for Profibus and PROFINET. PROFIsafe meets the highest safety requirements for the process and manufacturing industry with SIL 3 (safety integrity level) or category 4 according to EN 954-1.
Both safety-related communication and standard communication are possible via one and the same cable.
PROFIsafe protocol
The PROFIsafe system is an extension of the Profibus and PROFINET system. Freely programmable safety functions can be executed with the system and the required safe input and output data can be transmitted from and to the safe I/O devices.
Black channel principle
PROFIsafe uses the black channel principle exactly the same way as INTERBUS-Safety for the transmission of safe data via a standard network.
The safe data, consisting of the purely safety-related user data and the protocol overhead required for protection, is transmitted via Profibus or PROFINET together with data that is not safety-related.
The F host in the safe controller and the F device in the I/O module exchange safe signals in this way.
- Repetition of messages
- Loss of messages
- Insertion of messages
- Incorrect order of messages
- Data corruption
- Delay of messages
- Recurring memory error in switches
- Reversal of devices
Response time
The minimum distance of the safety equipment to danger depends on the following factors
- Delay time of the sensor
- Processing time of the safety program in the safety controller including the network transmissions
- Processing and filter times in the input and output modules
- Delay or overtravel time of the actuator
Due to unsolicited, unsynchronized individual processes, the response time is determined as the sum of the following values:
- Watchdog time of the input module
- Set watchdog time of the network from the input module to the controller
- Set watchdog time of the safe controller
- Set watchdog time of the network from the controller to the output module
- Watchdog time of the output module