Engineers guide to the ISIS polarisation module mimic.
1. Context:
This guide details how to use the isis polarisation module engineering
mimic for low level control and fault diagnosis.
2. Start up:
Logon to lpss8 as user 'isisp' with password 'wht_isisp' from a terminal
which can support an X session.
When logged on type 'start_eng' which will start the mimic.
3. Shut down:
Simply move the mouse pointer to a blank part of the mimic and click the
right mouse button.
4. Operation:
4.1 Displays:
The mimic has a number of displays arranged hierachically. To move down
a level move the mouse pointer over any text in blue eg 'Top Waveplate'
and press the right mouse button. This should bring up a small box with
the choice of options. For "top Waveplate' this is; 'slide', 'angle' or
'spin'. Move the mouse to highlight the desired choice and release the
button.
To move 'up' a level either move the pointer to a blank part of the
mimic and press the right button or press the 'previous screen' soft button.
The arrangement of displays is identical for both waveplates.
The top level display is informational only, it is not possible to alter
the state of any mechanism from here. The next level down allows functionality
similar to the VAX commands. i.e mechanism's will move in sequence if neccessary
for a particular movement. eg, release detent then move wheel.
The lowest level called 'engineering control' only controls individual
mechanism's. Therefore it is possible to attempt moving a detented wheel
without releasing the detent. Take care!
4.2 'Slide' display:
VAX level allows you to set a demand value of OUT or IN and then click
on the MOVE button to effect the move. The current position is reported.
At the 'engineering control' level the same movements are achieved by
clicking on the IN, OUT buttons. The move takes place immediately the button
is pressed.
4.3 'Angle' display:
VAX level allows a demanded angle to be entered and when the MOVE button
pressed the detent will release, the wheel moved and then the detent engaged
if relevant. The detent only engages for angles that are multiples of 22.5
degrees. The wheel may also be zeroset by clicking on DATUM.
The 'engineering control' level allows individual control of the detent
and wheel stepper motor. The detent is controlled by a latching pneumatic
cylinder. Clamp drive applies a current to the relevant coil. It should
be left in IDLE i.e no current flowing.
It is necessary to manually enable the stepper motor coil current after
having entered a demand position.
Encoder Mode can be set to NO if the encoder has broken. The software
does not then check the encoder value and runs open loop.
4.4 'Spin' display:
The VAX level allows a spin rate to be set and started with the MOVE button.
To stop the plate spinning enter a demand of 0. After the plate has been
stopped it will automatically do a datum set and leave the plate clamped.
The 'engineering control' level is similar to the angle display.
Spotty Barker 3/12/96