We have received (and tested) the first batch of circuit boards for the FPUs. Each FPU requires two circuit boards; the main drive electronics that attach to the base of the FPU and a smaller board that is mounted on the alpha stage of the FPU and relays signals from the motor and switches on the beta stage of the FPU. In Edinburgh we have received the first 100 of each of these boards – which is a fairly scarily large pile of boards!
Relay circuit boards, with the flexi cables that connect to the main drive boards.
The FPUs are controlled using 15 CAN Buses, each of which can communicate with up to 76 FPUs simultaneously. As can be seen in the picture below we have just completed (successful!) testing of the first fully populated Bus. Just as a note of reassurance, for the testing there are green LEDs on the boards to show things are working – clearly in the real instrument these will not be flashing away!!
Testing of 76 drive boards on a fully populated CAN Bus.