ESI CCD Electronics Manual
The Eshelette Spectrograph and Imager, ESI, instrument has been built by the Technical Facilities department of the University of California Observatories, Lick Observatory, UCO/Lick Observatory. This manual will cover the CCD Controller. The Instrument Controller is covered separately in the ESI Instrument Manual.
The CCD system consists of three components:
- CCD Crate
- CCD Controller
- CCD Dewar and electronics box
The CCD crate resides in the data taking room, the controller resides in electronics locker #2 on the instrument, and the dewar is attached to the instrument's camera.
The above drawing shows the cabling and relationships betwixt the boxes.
The CCD crate lives in the computer room and consists of a chassis with a horizontal 5-slot VME cage, power supplies, and cooling fans. The card complement consists of a Force 5CE CPU card, a Chrislan 256MB Memory board, and a SDSU2 VME interface card. This box provides the link between the CCD controller and the instrument computers. It connects to the CCD controller via a duplex fiber optic cable and to the instrument computer via a private net. The box serves as a buffer and protocol converter between the CCD controller and the instrument computer. The SDSU2 VME interface card communicates with the CCD controller and under the direction of the CPU board stores the CCD image into the memory card. The CPU card then formats the data and sends it to the instrument computer via the private network.
The CCD controller consists of at six slot 3U VME P1 backplane, power supplies, a Power Monitor board, and the following boards:
- SDSU2 Timing board
- SDSU2 Clock Generator board
- SDSU2 Video processing board
- SDSU Utility board
- EL-3193 Utility support board
- EL-3194 61-pin Cable Interconnect board
- EL-3195 Power and Miscellaneous Signal board
- EL-3198 Clock Cable Interconnect Type-1 board
- EL-3199 Bias Cable Interconnect board
- EL-1198 Power Monitor board
At the heart of the controller is the set of SDSU boards that generate the clocking waveforms and bias voltages for the CCD, digitizes the video output, and transmits it to the CCD crate. They also do the timing of the exposures, control the shutter, and control the temperature of the CCD. For more detailed information on the operation of these boards please see the software manual.
The UCO/Lick boards perform the following functions:
- The Utility support board interfaces the signals and I/O from the SDSU Utility board. This includes such functions as sending control signals and receiving status signals from the Power Monitor board, passing control signals and receiving status signals to and from the Shutter Controller. Passing the heater control and receiving temperature data to and from the dewar. And providing a path for reading back any of the clock waveforms or bias voltages.
- The 61-Pin Cable Interconnect board acts as a collection point for all of the signals that connect the controller and the dewar electronics box. It is mounted to a 3U panel that screws onto the back of the chassis.
- The Power and Miscellaneous Signal board is the source for the 17-pin power cable that connects the dewar to the controller. It passes the power supply voltages and the heater and temperature lines. It is also mounted to a 3U panel that screws onto the back of the chassis.
- The Clock Cable Interconnect board has a set of DB-37 connectors and it's 3U panel mounts to the front of the chassis. This board's function is to connect to the SDSU2 Clock Generation board via a single 37-pin ribbon cable and send half of the clocks to each of two 24-pin IDC connectors. This allows flexibility configuring the controller.
- The Bias Cable Interconnect board has a set of DB-25 connectors and it's 3U panel mounts to the front of the chassis. This board's function is to connect to the SDSU2 Video board via a single 25-pin ribbon cable and send half of the clocks to each of two 14-pin IDC connectors. This again allows flexibility configuring the controller.
- The Power Monitor board acts as a watchdog on the various power supplies and AC power. If any of the power supplies go bad the Power Monitor boards shuts down the controller. It also enforces a sequence in which the power supply voltages can be applied or removed from the backplane, and consequently, the clock waveform DAC.
CCD Dewar and Electronics box:
At the dewar there are two areas that contain electronics; the electronics box mounted on the outside of the dewar and the internal wiring in the dewar.
The internal wiring consists of the following:
- The CCD chip.
- The connector to the CCD chip.
- EL-1240 MITLL CCD Interconnect board.
- EL-1227 Dewar/Hermetic Connector board.
The Keck ESI CCD page has specifications of the MIT-Lincoln Labs 2K by 4K detector. The signals leave the CCD via flex-cable with a mini 37-pin DB connector. This connector is connected to a matching connector that is mounted onto Delrin standoffs. Due to physical requirements, the mating connector had to be mounted to the standoff and then hand wired to the EL-1240 board. The EL-1240 board is used to route the signals that come into the dewar via the EL-1227 connector board. It attaches to the EL-1227 board as a 'daughter' board by means of two Omhnetics 32-pin connectors. The board also has a 4-pin connector for the temperature diode and the heater resistor and SMB connectors for the video signal. The EL-1227 board is soldered directly onto the pins of the 61-pin hermetic connector.
The Electronics box contains the following:
- EL-1220 Dual Pre-Amp board.
- EL-3191 17-Pin Connector/Power Filter board.
- EL-3192 61-Pin Connector/Analog Switch board.
The Dual Pre-amp is connected to the dewar via coax cable. We are using SMA hermetic connectors to pass the signal from inside the dewar to the electronics box. We are actually using one hermetic SMA to pass the video signal and a second to pass the return line so that the signal is isolated from the case. The pre-amp is a discrete non-inverting amplifier with a gain of 5.5 (see the EL-1220 board description for details.) The power supply voltages come into the dewar electronics via a 17-pin cable that connects to the EL-3191 board. The 17-pin connector is soldered directly to the board and the board is mounted onto the electronics box. This board has filtering and connectors for up to four CCD video signals, two Dual Pre-amps, and four Analog Switch boards. The 61-Pin Connector/Analog Switch board is also mounted to the case via a solder tail 61-Pin connector. This board contains the analog switches that control application of the clocking waveforms and bias levels to the CCD. These switches reside in the dewar electronics box so that they are as close as possible to the actual CCD. This allows them to also act as buffers or isolators to the CCD signals so that none of the CCD's pins are directly exposed to external induced voltages or static discharge. This board also provides the connectors necessary to cable to the 61-pin hermetic connector to the dewar interior.