2011-03-03 SAFARI software and hardware setup

Below is a basic setup of our software and electronics.

SAFARI setup software and electronics

We have two PCs, one with our Generic EGSE software and the other with a daemon (which collects data). To give you an idea, the Generic EGSE looks as follows:

EGSE Server.png

The daemon just receives data on an optical ethernet port in raw ethernet frames, then concatenates the packages and transfers them over TCP to the EGSE server.

The reason we use a separate PC for the daemon, is that the EGSE server cannot natively receive data over raw ethernet. Thus we use a daemon for that and the data rate is too high to run both daemon and server on one PC.

The demux is short for 'demultiplexer board', an electronics board:


This board retrieves the science data from the sensor and then decimates it. There are two filters available for that. Still, the amount of data is considerable. An ethernet frame can contain 1500 bytes of data. Since one sample of the sensor is two bytes, we put 730 samples in one CCSDS packet so it fits into one ethernet frame. A good sampling should take 100,000 samples. This is rather a lot of packets so you'd say this could easily be fitted into jumbo frames. However, the demux board firmware doesn't support jumbo frames. So we concatenate the CCSDS packets on the PC with the ethernet daemon, then transfer them over TCP to the EGSE Server.