Cabling and Data Transfer

The following summarises the current cabling installed on the 200inch telescope. We describe how signals from both benches are carried to the computer room that is the central hub for communications. From this location signals can be routed to the data room in which the diagnostics pc for this run will be located.

Current cabling existing at 200inch:

o There are (27) 50-ohm coax lines, (12) 62.5u multimode fiberoptic lines, and (120) general-purpose copper conductors at the prime focus cage.

o All the fiberoptics have ST-type connectors and run to the Cass cage, whence they can be routed to the computer room (CR).

o Six of the coax have BNC connectors; they run to Cass and can be continued to the CR. Fourteen coax have specialized Amp "coaxicon" connectors, but breakout cables can convert these to BNC-- these also run to Cass and potentially to CR. and seven coax run directly to CR.

o The plain conductors, while probably not of interest, run either to Cass or CR.

o It appears that LLT currently uses up to eight of the coax for existing functions, and none of the fibers.

o The cabling distance PF<->CR is ~100meters.

o We currently have (14) 50-ohm coax lines between coude and the computer room. No fiberoptic... but it is a short run and we can run some F.O.cables if that is needed.

Suggested cabling method:

Coude to computer room:

o 3 analog cameras

o 1 photodiode analog output &#61664

Use 4 × 50ohm lines

LLT to computer room:

4 analog cameras

1 photodiode analog output 

1) Analog to GigE IP engine (Pleora) located at prime focus (up to 6 analog inputs, 2 simultaneous)

2) 1000BaseT(GigE)->1000Base-SX(short wave optical fiber) converter located at prime focus (arrived)

3) 100m of 62.5 multimode fiber to computer room

4) 1000Base-SX->1000BaseT converter located in computer room (arrived)

5) GigE into PC PCI card (Patrick has supplied a PCI single GigE card for testing)

-- AnnaMoore - 30 Sep 2006