DEIMOS has removable elements: slitmasks, filters, and gratings. In the final deployed state, all these elements should be barcoded. The slitmask barcodes can be read by a scanner mounted on the instrument. The other element barcodes can be read by a hand-held gun which will semi-automate the configuration process.
In the short term, however, we have to configure gratings and filter wheels manually.
The dispatcher (Dean's code) knows the Raw, Ordinal, and Name values for each of N positions on a filter wheel. It also knows the Names that go with the Positions for the compound grating select/clamp stage. This knowledge is compiled in.
To "teach" the dispatcher new maps (either new raw positions or new names for existing positions) you need to feed it a "dyna map" file, which is generated from data in the database. Our dispatchers are configured to read this file at startup time, overriding their default (compiled-in) information with information from the file (which came from the database).
The observer GUI uses information directly from the database to configure its menus for filter wheels, grating select, etc. -- otherwise the menus would show the same choices that are compiled into the dispatcher.
The bottom line is that if you don't update the database to reflect the new configuration, the dispatcher won't know about the new filter, grating, or whatever positions; and the automatically-genned dashboard menus will be all wrong.
Here's the good news: the procedure is quite simple. Type a command, edit a file, type a command, restart the dispatchers and dashboards. [There are some warnings and caveats which you should read and understand before you get started.]
Here's a chunk of the cfg file.
# DWFIL # (dynamically configured) deimot DWFIL 0 1 Filter1 deimot DWFIL 142857 2 Clear deimot DWFIL 285714 3 Filter3 deimot DWFIL 428571 4 Filter4 deimot DWFIL 571429 5 Empty deimot DWFIL 714286 6 Filter6 deimot DWFIL 857143 7 Filter7 # (factory defaults) # deimot DWFIL 0 1 Filter #1 # deimot DWFIL 142857 2 Filter #2 # deimot DWFIL 285714 3 Filter #3 # deimot DWFIL 428571 4 Filter #4 # deimot DWFIL 571429 5 Filter #5 # deimot DWFIL 714286 6 Filter #6 # deimot DWFIL 857143 7 Filter #7If you read the comments at the top of the file (you did read all the comments, right?) you will know that the commented-out lines are the default (compiled-in) values, and the uncommented lines are your own (dynamic) values.
If you want to add a new filter at position 6, you would simply use your text editor to change the name "Filter6" to the name of your new filter, and then save/exit.
If you are moving grating cells around it is slightly more complicated. The grating stage (GRATExxx keyword) is actually two stages, a linear motion stage and a clamping mechanism. GRATEPOS and GRSELNAM are more or less equivalent: for consistency and to avoid confusion, GRSEL has to know the same named positions as GRATE. Therefore there are two blocks of text to edit for this stage, if you want to do it right.
# GRSEL # (dynamically configured) deimot GRSEL 10000 1 NonOp deimot GRSEL -9323100 2 Mirror deimot GRSEL -4228176 3 900line deimot GRSEL 128228 4 1200line # (factory defaults) # deimot GRSEL 10000 1 Grating_1 # deimot GRSEL -9323055 2 Mirror # deimot GRSEL -4218400 3 Grating_3 # deimot GRSEL 126012 4 Grating_4 # [...] # GRATE # (dynamically configured) deimot GRATE 1 1 NonOp deimot GRATE 2 2 Mirror deimot GRATE 3 3 900line deimot GRATE 4 4 1200line # (factory defaults) # deimot GRATE 1 1 Grating_1 # deimot GRATE 2 2 Mirror # deimot GRATE 3 3 Grating_3 # deimot GRATE 4 4 Grating_4Usually we're swapping the 1200 line and 900 line gratings between slider 3 and slider 4. Just change 900 to 1200 and 1200 to 900 in both locations, then save/exit.
What if there are no uncommented lines for this stage -- i.e. you are the first on your block to populate a filter wheel with real filters? Easy. Copy/paste the commented lines to duplicate them. Uncomment the duplicate copy. Get rid of any positions that you don't want to see in menus. Change the names of those you do want to see, to reflect the actual filters now installed.
The biggest warning of all is that this procedure will NOT provide the "FITS mask chunks" to be appended to DEIMOS images. To provide the FITS mask chunks you have to run dremel. There is still no graceful workaround for a mask whose barcode cannot be read (we're working on that).
The Surgeon General has determined that it's very bad for everyone's mental health when the ordinal positions of DC stages get messed up. Therefore, unless you really know what you are doing, please don't touch the raw or ordinal positions in the config file; restrict yourself to the names of the positions.
If you mess up the file unintentionally (an editor mishap) don't panic, just quit without saving and start over. If it's too late for that, then just run confget again and start over. As long as you haven't run confput, nothing has happened that anyone else can see.
Don't imagine that you have to add to the cfg file every unload position, home position, etc. -- those are not dynamic, and they will always be compiled in to the dispatcher and available to engineering GUIs. Restrict yourself to naming the positions that observers actually see in menus and scripts.