LRIS Upgrade - EL-4250

As shown on the EL-4350 drawing, sheet 1, the main electronic components of the dewar focus stage are the 24VDC power supply, the Galil CDS-3310 motion controller the stage motor with its encoder and the Siko load encoder. The SWS100-24 power supply is an off-the-shelf Lambda 24V DC switch-mode unit capable of providing 24V at up to 4.3 amps. This supply powers the controller and the motor. The Galil CDS-3310 single axis controller uses the familiar Galil instruction set and provides the normal stage I/O of past controllers. These include forward and reverse limit inputs, home input, and motor and load encoder inputs. It also includes a newer feature that we have taken advantage of - a dedicated Brake output. This feature allows the controller to accept a 24V supply input that is used to energize a normally on brake to release it. The output is controlled via the SH, Servo Here, command and the MO, Motor Off, command. The brake used is a Electroid FSB-1-4-24V normally engaged brake. The stage motor is from Dynetics Systems with a Renco encoder attached. The servomotor consists of a Dynetics Systems MS15 type DC motor and a Renco modular 250 line, 1000 quadrature counts per revolution encoder. The resolution of the motor encoder workes out to 0.13microns of focus/encoder count. The encoder was attached to the motor at the Lick shops. The load encoder is a Siko MSK1000 hall-effect unit with a resolution of 5 micron/count (5*1/7.5wedge = 2/3micron of focus).

The diagram also shows the EL-5008-B circuit board that inserts a Tyco/RayChem polyswitch in line with one leg of the motor power. The polyswitch acts as a resetable fuse to protect the motor from drawing to much current. The device used is a RXEF160 with a holding current of 1.6 amps at 20 degrees C and 1.9 amps at 0 degrees C. The device will act as an open circuit when tripped but will rest when the motor voltage is removed.

Notice on the Galil controller block J3, the digital input IN2 and IN4 are wired to grounds associated with the two encoders and provide cable connected signals.

Sheet 2 of the schematic shows the wiring for the Home and Limit switches. J3 shows the straight forward wiring of the power and signals. The connections are made to the 10-pin connector at Keck's JT17. This is a PT02 size 12, 14-pin connector.

Sheet 3 is divided into two sections. The upper portion details the wiring for the CCD shutter. The shutter connections consist of solenoid wiring and limit switch wiring. The limit switches are standard limits from microswitch and the bottom is a sketch of the custom cables made for the stage.
Starting on the right side, the shutter wiring shows the limits and solenoids connect to 4-pin and 3-pin Molex connectors. These connectors are locates within a few inches of these components and allow for easy acces for direct testing of the components. These two connectors then wire to a DB-9 connector located at a convienent place on the focus stage to allow the stage to be easily removed from the instrument. The final cable connects to the Keck provided bulkhead connector.