Performance
The PROFINET RT data packages are transmitted to both the controller and device at a constant send clock. If this send clock cannot be maintained, then the connection is terminated by the communication watchdog "DataHoldTimer" of the PROFINET Devices, even during the phase of establishing a connection.
On weak systems or systems with a poor link to the Ethernet component (SysEthernet
), unstable data transmission can occur.
Then either the send clock has to be reduced in the Reduction ratio
setting, or the communication watchdog has to be intensified. The performance of the CPU is less important for the performance of the PROFINET driver. The link of the Ethernet interface is decisive. In addition to the hardware, the software-specific link (operating system and Ethernet drivers) also plays an important role.
Examples of a possible number of connections and send clock:
OS | CPU | Connections * send clock |
---|---|---|
Windows (RTE) | Atom | 50 * 1 ms |
VxWorks | Power-PC | 30 * 4 ms |
Linux | Raspi V3 | 6 * 1 ms |