In the field of industy automation there is a trend to use Ethernet as a field bus. The time delays between the individual modules are very important. For a research project of the ZHW these transmission times must be measured. In this diploma project a suitable measurement device operating in a 100Base-TX network shall be developed.

The analyser must be able to recognize electrical signals and ethernet packets as events. In order not to affect the traffic on the ethernet, the signals had to be connected with high-impedance devices. Because there is more traffic on the ethernet segement, an option must exist to selecet only certain packets.

The selected solution consists of a PCB which is plugged into a host computer. We chose a PC with a PC/104 bus as host. The widely used PC/104 bus is electrically identical to the ISA bus but uses another physical connector. To be able to place all required components a four layer PCB was required. A few op-amps allow the monitoring of the ethernet. A device by National Semiconductors decodes the physical layer of the ethernet. An FPGA saves all occuring events with a time resolution of 20ns. The FPGA was programmed in VHDL. It also represents the PC/104 interface to the host computer. A demonstration software under Debian GNU/Linux shows the functionality of the hardware. By means of an easy-to-use GUI it also allows the implementation of a specific software solution for the measurements in industry automation.