Automation technology requires linear network structures, which have been proven in the established fieldbus technology. This leads for Ethernet to devices with two ports, internal switch or hub functionality and to critical requirement regarding propagation time and jitter, if a Real-Time Ethernet protocol is used.

Analyzer software programs, Wireshark is probably the most known, are license free available in the internet and use the Ethernet ports of a PC as analyzer hardware.

Additionally so called TAPs are necessary to get a connection into the Ethernet cable. Delay measurement at full duplex mode requires four record channels which are more ports as available on a PC. Time measurement with PC accuracy results at the best to resolutions in the area of micro seconds, but this needs to be better with a factor of 1000.

The netANALYZER, an intelligent PC card, possesses internal TAPs and captures two Ethernet connections bidirectional. Each Ethernet frame gets a time stamp with a resolution of 10ns. With this, delay times and jitter can be measured. For further analysis this data can be transferred to Wireshark with the open WinPCAP format. Plugins for Wireshark are available for the EtherCAT and various other Ethernet based fieldbus protocols. In fact, everyone implementing a Real-Time Ethernet protocol into a device should have a network analyzer.

The Ethernet cable of the device unter test are connected to the internal TAPs of the netANALYZER. For this, usual patch cables can be used. Start and stop of capturing respectively examitation of delay and jitter can be controlled by the netANALYZER program. The data is stored on the hard drive then. Wireshark can access this data and display it. For examination it is recommended to use the free plugin which are available in the internet for EtherCAT and various other Ethernet based fieldbus protocols.





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