Shane AO Electronics

Shane AO Fold Mirror #1 Stage, EL-3811

Schematic: schematics\AO_fm1_sh_1.pdf
Page last updated: November 20, 2012


Simplified Diagram - Refer to first page of schematic for more details


The Adaptive Optics fold mirror #1 optically consists of a set of two prisms. One prism is fixed and the other moves either toward or away from it. From a control standpoint, the stage consists of a motorized stage, encoders, a HOME sensor, and limit switches. In the above drawing, the control system is shown on the left and the stage is on the right. At the heart of the control system is a Galil Motion Control DMC-2280 controller. In concert with the Galil AMP-15940 servo amplifier, the controller provide precise motion control for each of the APF stages. The Kepco 48V power supply provides power to run the motors and the Kepco 5V power supply provides power for controller I/O. Note: Quick Start and Operator manual links for the Kepco supplies can be found on the APF Documents web page and complete manuals are available at the APF dome. In the center of the above diagram, the blue blocks represent the various breakout boards built especially for the APF spectrograph electronics. These boards combine stage signals and power from various points in the electronics rack to feed the stage cable and motor cable and then break them back out for easy connection to elements of the stage within the spectrograph. The right side of the drawing shows the stage elements. Unlike the six other stages of the spectrograph, the ADC has only a reverse secondary limit. Due to the need to move the two prisms as close as possible to null them, there is no room for a forward secondary limit. To be clear, the forward limit of travel is where the two prisms nearly touch. In case of a failure of the primary and software limits, a Raychem 1.6A Polyswitch re-settable fuse , photo 13 below, is used to remove current from the motor. The ultimate end of travel of the stage is were the moving portion hits the end of the nonmoving end of the stage. At this point, the prisms are still separated but if allowed, the motor would draw more and more current. The re-settable fuse will heat up and disconnect the motor from the circuit. To reset the fuse power needs to be removed from the circuit. This is the only case in the APF spectrograph where a secondary limit does not report back to the software that the condition exists.



Sheet 2 SAO_fm1_sh_2.pdf


Simplified Diagram - Refer to second page of schematic for more details



Field Mirror #1, Tip Axis

The above drawing is provided.




Sheet 3 SAO_fm1_sh_3.pdf


Simplified Diagram - Refer to second page of schematic for more details



Field Mirror #1, Tilt Axis

The above drawing is providedd.