Transcript ZTFInterconnectScheme.ppt

ZTF Interconnecting Scheme
Stephen Kaye
2013-4-22
Telescope Diagram
• Telescope 6 m high with
48” (1.22 m) aperture
• Slight angle (3º) of
telescope body
• Detector mounted at 3 m
location in middle of
aperture
Detector
Spider
Hatch
• Spider mounts detector to
telescope
• Hatch near spider for
routed cables
• Mount electronics rack
near hatch
Electronics
Rack
Telescope Body
Connectors
• Pin outs are listed in
Excel Spreadsheet
• Three connectors for 2
CCDs
– 2 Micro D Connectors
– 1 ERF8 Connector
• Connectors split by
function
– 1 Bias connector
– 1 Clock Connector
– 1 Video Connector
Slot layout
Digital
Card slot width TBD:
•If 1” per card, two
rows required.
power
6U card slot
•If 0.8” per card it all fits
in one row.
•May need 1” for trace
routing down to cable
connectors.
•Is there room for plug
in supply module or
does this go in base (or
top of enclosure
analog
Video
Clock
Bias
1U
extension,
can increase
to 2U
Cables exit out of page, then turn.
Cooling infrastructure behind
connectors, maybe power supply too.
Controller Rack
• Mount 8 sets of cards in
chassis
• Chassis is 19” rack
mountable
• Customized backplane
fitted to off the shelf VME
crate
Max = 21 slots
*0.8” = 16.8”
VIB Board
• Same connectors will be
mounted to VIB board
• Off the shelf cables can
be used for harnessing
• Connectors at edge are
outside the dewar
vacuum
Card features
• Front panels for full shielding.
• No connections to CCD from front panel; maybe some
test points (eg BNC) or indicators.
• LED/indicator power toggled on/off by momentary
switch. Turns on at power up. Turns off whenever
software initialized.
• All cards have ejectors and locking screws.
• All cards can work on card extender.
Backplane connector features
• Multiple pin lengths (eg see 2mm hard metric or “metral”
connectors used in Compact PCI.) support:
– ESD to ground and supply instead of signal (CCD) pins.
– Accidental hot swap not catastrophic.
• Prefer connectors along long dimension (height) of card so
fewer columns of pins (often called rows) are needed: easier
to route traces.
• Shielded connectors available (probably not needed).
• Wrap tail pins on backplane serve as test points or jumper
locations.
– Can be cut short for speed critical pins.
– Can be covered with insulative sleeve for CCD outputs that are
vulnerable to shorts though we have none since we have preamp
in dewar.
Other features for electronics box
• Closed to external air/dust; minimizes hot air leakage.
• Heat exchanger, liquid cooled?
• Forced air recirculation or conductive via shield plates
between slot?
• Decision is yet to be made on supply packaging, either:
– Modular, plug into backplane (easy to replace)
– Flat supply module directly mounted to heat sink (easy to cool)
• Power supplies:
– Standard voltages: 3.3V, 5V, 12V, 15V
– Current consumption TBD, ….please advise.
• Power connector, switch, indicator and fuse on front
panel