HBAR was developed as a joint effort between AOA and MPIA. HBAR includes these major components:
* Sun Spark work station with dual monitors (MPIA).
* User interface, and real-time software server (AOA).
* Real-time VME based processor and VX-Works for the wavefront sensor function (AOA).
* Real-time software (AOA).
* Optical Enclosure Input Output (AOA).
* Stage Driver Back Plane (SDBP) chassis. (AOA/MPIA).
* Stepper motor controlled stages (AOA).
* UFORIA high speed fiber optical digital links (AOA).
* Fast framing wavefront sensor camera (Lincoln Labs/AOA).
* Fast framing camera power supply (AOA).
* Real time VME based processor for the tracker function (MPIA).
* Tracker camera, tip tilt mirror and drivers (MPIA).
* Deformable mirror driver (Xinetics/MPIA).
* Deformable mirror (Xinetics /MPIA).
The major system elements are shown in the figure 4.1
FIGURE 4.1 Electronic System
Provided by MPIA.
AOA developed the wavefront sensing user interface data capture and display software and system control software. The Sun work station is the host which boots the wavefront sensor VME processor. The software communicates with the various system elements and other computers over ethernet.
The real time processor has a 68060 CPU running VX-Works real time operating system and five (5) Ariel DSP processors. The Ariel boards capture the Lincoln Lab camera data and compute gradients and perform the reconstruction algorithms for the wavefront sensing function. A VME-UFORIA card is installed in this chassis for real time data communication from the camera and to the deformable mirror.
The real-time code for wavefront sensing and closed loop wavefront compensation was developed by AOA. This code runs on the Ariel DSP cards and is downloaded by the Sun work Station.
The Optical Enclosure Input Output (OEIO) board is used as an interface between the external MIL-38999 cables and the optical bench cables to the various stages and actuators. Signals for the OEIO originate in the Stage Driver Back Plane chassis (SDBP).
Two OEIO boards are used in the HBAR system. Board No. 1 interfaces to the stages controlled by AOA while Board No. 2 is used for the MPIA controlled stages.
The connectors to the external MIL-3899 cables use N keying for board No. 1 and A keying for board No. 2.
The OEIO has twelve (12) DB25s connectors for stage drive and control. Three (3) additional DB15s connectors are provided for spare signals. Board No. 1 (AOA) has two of the spare connectors assigned for control of the shutter and reference lasers.
The OEIO stage feedback inputs are equipped with buffers which can be set to convert single ended feedback signals to differential signals.
The connectors on the OEIO have a cable connect detection pin. A global ALL_CONNECT signal is sent to the stage driver back plane (SDBP). This signal can disable the entire stage control system if a cable is left unconnected. This function can by disabled with configuration jumpers.
The Stage Driver Back Plane board is located in a 1U VME chassis. The SDBP can accept six (6) stage driver (ALPHA-1) cards. The chassis is equipped with one 42 Volt, 6A unregulated power supply and one triple output (+5V, +/-12V) regulated power supply. An optional +24V power supply may be connected to the SDBP PCB to drive optional brake circuits. The +24V supply is NOT present in the chassis.
Each ALPHA-1 card has two Integrated Motion Systems (IMS) stepper motor driver modules. The ALPHA-1 cards were designed and furnished by MPIA. Each IMS module must be configured for party line use and have a unique address assigned to it before installation into the system.
Two SDBP chassis are used in the HBAR system. Chassis No. 1 interfaces to the stages controlled by AOA while chassis No. 2 is used for the MPIA controlled stages.
Each chassis has an RS-232 input for control. Optionally, the second chassis may be slaved to the first chassis via RS-422 ports.
The connectors to the external MIL-3899 cables use N keying for board No. 1 and A keying for board No. 2.
The external MIL-3899 connectors on the SDBP are integrated into the cable connect detection logic located in the OEIO board. The ALL_CONNECT global signal can be used to disable the stage drivers. This function can by disabled with configuration jumpers.
There are twelve motors controlled by the AOA SDBP chassis.
An example of the AOA stage assignments follows:
|
FULL NAME |
FUNCTION |
OEIO #1 CONNECTOR |
OEIO IMS ADDRESS |
Software Name |
|
Shutter and Driver, +24V |
Shutter Power and Trigger |
J015 |
a |
fsmTip |
|
Reference lasers (two) |
Switched Reference Laser Power |
J016 |
a |
fsmTip |
|
Field Selector Mirror Mount |
Tip |
J01 |
a |
fsmTip |
|
Field Selector Mirror Mount |
Tilt |
J02 |
b |
fsmTilt |
|
Hartmann Lens Array Selector |
MLM selector (5) |
J03 |
c |
hlas |
|
Relay Lens Mount |
|
J04 |
d |
rlm |
|
Wavefront Sensor, MIT/LL CCD Stage |
Position Camera |
J05 |
e |
wfs |
|
Tracker X - CCD Mount |
X |
J06 |
f |
tcx |
|
Tracker Y - CCD Mount |
Y |
J07 |
g |
tcy |
|
Tracker Z - CCD Mount |
Z (focus) |
J08 |
h |
tcz |
|
Field Stop - Reference Fiber Selection |
Field Stop - Reference Select |
J09 |
i |
fsrfs |
|
Field Stop - Reference Fiber - Z axis |
Field Stop - Reference Select Z Axis adjust |
J10 |
j |
fsrfz |
|
Tracker Filter Wheel |
Select Filter (5) |
J11 |
k |
tfw |
|
Wavefront Sensor Filter Wheel |
Select Filter (5) |
J12 |
l |
wfsfw |
The Universal Fiber Optic Repeater and Interface Assembly (UFORIA) provides two high-speed links. One link interfaces between the Lincoln Labs fast framing camera and an Ariel `C40 port. The second link connects between an Ariel `C40 output and the Xinetics deformable mirror.
The board was designed as a combined transmitter/receiver pair in a 6Ux160 mm form factor, but with break-away option such that the PCB can be cut in half and located in separate enclosures for remote point-to-point operation.
The combined UFORIA-VME is used in the VME chassis. The split UFORIA-T and UFORIA-R are used for data transfers from the Lincoln Labs Camera and to the Deformable mirror respectively.
The Link speed has maximum speed of 100 Mbytes/second synchronously and 50 Mbytes/second asynchronously. HBAR runs at a rate of about 20 Mbytes/sec.
The fast framing camera has a 256x256 cooled pixel CCD device with 6 electron noise specification. The maximum frame rate is 1200 frames per second.
The sensor, analog electronics and timing board were developed at Lincoln Laboratories. AOA provided a microprocessor controller, quad digitizers, high speed digital port and an RS-170 video port for viewing the WFS image. This feature facilitates alignment of the camera.
AOA designed and built a 19" rack mounted power supply for the fast framing camera.
MPIA designed and provided a VME rack for collecting data from the tracker camera and to drive the tip tilt mirror.
The tracker camera is provided by MPIA. It is manufactured by Astromed. This camera mounts on an xyz stage located within the AOA wavefront sensor. AOA controls the motion of this stage. The drivers for the tracker were provided by MPIA.
The deformable mirror has 97 actuators and is manufactured by Xinetics. This subsystem was CFE.
The DM driver is CFE also manufactured by Xinetics. The mirror is controlled by the AOA real-time wavefront sensor processor. The communication link through the UFORIA interface.