HIRES CCD Controller Electronics
This section contains descriptions of the overall electronics for the HIRES CCD controller.
Interconnection Diagram,
EL-3411
Schematic: schematics/Intercon.sch.pdf
Page last updated:
August 2, 2004
The HIRES CCD controller interconnection diagram shows how the various components are wired within the CCD Controller box. A wide line that runs from the upper left left corner across the top, down the right side and across the bottom of the diagram. This line represents the VME type backplane that is mounted in the chassis. Into this backplane the SDSU2 (Leach 2) boards are plugged. The controller has six video boards, two clock boards, and one each timing and utility boards. These boards make up the functional controller. The UCO/Lick Observatory style controller adds extra functionality and makes many of the SDSU2 functions modular. Modularity is achieved by grouping sets of signals in logical divisions. For instance, the SDSU2 Clock board has enough clocks to run two different CCDs. A Lick board accepts signals from two SDSU2 Clock boards and breaks them into four sets of signals that are then available on four standard IDC connectors. This is of importance when building controllers for mosaics where there are multiple CCD's because it makes the interconnecting of signals much more manageable. The same type of regrouping is done with the bias voltages generated on the SDSU2 Video boards. These functions/boards are shown as the long rectangle boxes on the diagram. The three EL-3194 61-Pin Cable Interconnect boards in the center of the diagram act as a collection point for the signals needed for each CCD. At the top of each of these boards are two input connectors that connect the bias voltages from the Bias Cable Interconnect boards. The connector at the bottom, P2, brings in the needed clocks. There is also a cable that connects each of the Cable Interconnect boards to the Utility Support board. These cables provide wiring for the heater resistor and temperature diode but they also provide some of the extra functionality mentioned above. These cables contain a set of signals to control a analog multiplexor on the Cable Interconnect board. These are four address lines and an analog level signal. The Lick software on the SDSU2 Timing Board has the ability to control these line to select any of the bias levels that are being supplied to the CCD. The software in fact checks that each voltage is within specs as part of the controller start routine. In the upper right corner of the drawing are the video output lines from the preamps. They are coax cables wired to the front of the SDSU2 Video Boards. (Though they physically exist, three of the coaxes are not in use at this time). Looking at the lower rectangular box on the diagram, there are two coax cables run from the SDSU2 Clock boards to the Utility Support boards. These connectors supply an analog signal from the clock boards that can be programmatically set to the output of any of the clocks generated on the boards. Again, at start up, the Lick software selects each of these one at a time to verify that they are all within specs.
On the left side of the drawing are more of the Lick support boards; the
Power & Miscellaneous Signal board and the Utility Support board. The
Power board has two main functions. First, the 17-pin output connector supplies
the analog supply voltages for the dewar along with the heater, temperature
and analog switch enable signals. The second connector, P2, provide the other
maintenance functions for the system. These functions are the LN2 fill system,
cooling fan control, and shutter control.
The Utility Support board acts as a buffer and traffic director for all of
the available I/O on the SDSU2 Utility board. The CCD controller software
assigns functions to the various I/O bit. To view the signal assignments,
see EL-3420. The Utility Support board
also provides opto-isolation for I/O that is wired to the 'outside world'.
As an example, the shutter control line and it's input line each are applied
to an opto-isolator to ensure that the CCD controller I/O lines won't be subject
to any shorts, etc.
The Utility Support board has a total of 19 connectors. HIRES uses the following:
CONNECTOR |
FUNCTION | |
P2 |
Cable from SDSU2 Utility board | |
P4, P5, P6 |
Cables containing bias select signals for reading back bias levels, heater resistor and temperature diode signals and +5V, +16V, and -16V power. | |
P7 |
+5V for Utility support board, +/-16V for running DACs on video boards for before the +/-16V lines to the backplane is turned on via software. | |
P9 |
Control and monitor signals for Power Monitor board. | |
P14 |
Shutter signals, auxiliary heater and temperature diode signals (when used), and Analog Switch Enable signal all going to the dewar electronics box. | |
P15, 16 |
Selectable clock monitoring line. These coaxes connect to the two SDSU2 Clock boards and are used to monitor the clock waveforms. Each clock can be selected via software. |
Lastly, in the bottom center of the diagram is the SDSU2 Timing board that runs the system. Note that it has a pair of fiber optic cables that talk to the data taking computer.