How to configure DEIMOS with Removable Elements

Procedure and Components

De Clarke, UCO/Lick, Jan 2002

There are three sets of removable elements which can be removed and installed in DEIMOS: filters, gratings, and slitmasks. Configuration consists of four related activities:

Under normal circumstances, the last three actions are all taken care of as one, by the "COMMIT" operation of the dremel auto-configure daemon. Under exceptional circumstances, workaround commands and tools may be needed to complete the configuration (see end of document for Workaround scenarios).

The physical configuration is simple (detailed procedures are documented below).

For each stage with removable elements there is an access hatch allowing you to get at the stage and replace/remove/install elements. These hatches are clearly labelled.[picture] Basically you open the hatch, move the stage to its unload positions with local push button controls, and remove and install elements as required; when done, you close the hatch. What's different about DEIMOS is that under normal circumstances you can configure the instrument as you go, using a hand held barcode scanner, instead of having to type element names into some kind of GUI as a separate activity later. can

To configure DEIMOS:

The filter and grating cases are heavy. If you have to carry both of them plus slitmasks (which for this instrument are large), a rolling cart might be the best way to transport the stuff. You will also need a large standard screwdriver for releasing the half-turn catches which secure the access hatches.

Once you are on the platform with your element cases and your screwdriver, find the rotation control handpaddle [picture]

Set the small toggle switch to "MANUAL" instead of "COMPUTER". This gives you manual, local control of the rotator and locks out all remote control.

Rotate DEIMOS so that you can access the hatch for an element you want to change. Open the hatch and follow the correct procedure for removing/installing that type of element (for handling and access procedures, click on any of the next three links):

Once you have finished installing all desired elements for the night, use the hand-held barcode scanner (the 'bargun') to scan the command code labelled "COMMIT" which will be found on a laminated sheet of barcodes affixed to the instrument. After you hear the confirming buzz from the annunciator hardware, you can walk away from the instrument; the remaining steps are done in the control room. You and your cart can now go downstairs again.

DO NOT FORGET to use the toggle switch to put rotation back in "COMPUTER" control mode. If you leave it in MANUAL mode, the instrument won't work for observing.

OK, now you are downstairs again in the control room or any other room where you can log in to the machine keamano as the user dmoseng.

The first and easiest test you can do is to choose the "DREMEL Verify" option from your main menu. This will run tkremel, a small GUI which shows you the configuration created by the procedure you just followed.

You can use tkremel to alter the "GUI Names" of filters, gratings, and masks. However, be aware that these names are semi-standardized and will appear in the image FITS headers. Don't change them except in unusual circumstances; for example, when an observer has brought a private filter which doesn't have a barcode and you need to assign a name to that slot.

There is a COMMIT button on tkremel which can be used to re-commit (override) GUI menu and dispatcher configuration information.

tkremel allows you to proofread the basic configuration of the instrument, i.e. that the GUI menus and the dispatchers should be in agreement. Because DEIMOS is more complicated than the average instrument, there is another level of configuration to be verified. Choose the "Check Files" option from your main menu to verify that important configuration data files have been written to the correct locations by the COMMIT command you sent to dremel.

WORKAROUNDS: if for some reason the normal procedures described above don't work, see the following Workaround Pages for manual (i.e. command-line) methods of configuring the instrument.
De Clarke