ICIMACS for the MSU 2Kx2K Camera: Software Notes

12/18/97 : JAM

(ICIMACS = Instrument Control and Image Acquisition System)


SCSI Bus Activity:
Any other computer sharing the SCSI bus with the IC must limit its bus activity. The computer should only stay on the bus long enough to transfer images to their final location, as the IC can't tolerate long delays in accessing the bus.

ZOOM and STATS commands:
The ZOOM and STATS commands have not been fully debugged yet, and I'm certain there are many ways to crash the acquisition program with these commands. My advice is to set these up once at the beginning of a run to useful values, then leave them alone.

First time set-up:
Because of our need to set up and test the camera in a lab environment before delivery, some of the initialization variables will be set to values that may be annoying to an observer trying to take data. In no particular order:

FLASH sets the LED flash timer on our lab image projector. Setting this to zero (FLASH 0) will speed up acquisitions.

TCENABLE The IC will try to get telescope information for the FITS header if the TCENABLE keyword in HAWLEY.INI is set to T. Set this to F to speed up acquisitions, unless you have written the code to provide the telescope information in the format expected by the IC (see below in Telescope and instrument controllers interface).

OBSERVAT,TELESCOP,LATITUDE,LONGITUD,ELEVATIO are the FITS header keywords that describe the site you are using. Enter the correct values for your site in FITSMSU.TPL

DETGAIN is the FITS header keyword that gives the detector gain. After determining the detector gain experimentally, enter the value in FITSMSU.TPL.

COMMENT Add as many comments to the FITS header as you like with this keyword in FITSMSU.TPL. HISTORY is an alias for COMMENT.

Overscan and Binning
The overscan taken by the IC may be changed automatically following changes in binning. This is done in order to keep the number of overscan pixels a multiple of the binning factor.

Dark Columns and Binning
X-axis binning values that are not factors of the number of data pixels will result in evenly spaced dark columns in the image. These are due to data pixels being binned with overscan pixels in the final image.

Overscan; entered values versus number of pixels
The definition of overscan used in ICIMACS refers to physical clocking of the detector phases, not to the number of pixels that are found in the final image. The difference between these values is a function of the on-chip binning used and the number of amplifiers present. For example, if the command OVERX 8 is entered, the detector phases will be clocked 8 times past the end of the usable data. In an unbinned image, this will give 32 overscan pixles in the image, 8 for each of the 4 amplifiers. If the binning is set to 2, 16 overscan pixels will appear in the final image. If binning of 3 is entered, the program will automatically increase the OVERX value to 9, so that the number of clocks is an even multiple of the binning factor. The total number of overscan pixels in the final image in this case would be 12.

Note that the FITS header reports the physical clocking of the detector as the overscan (OVERSCNX,OVERSCNY), not the number of overscan pixels in the image

Mount points on startup
A valid mount point must be explicitly selected on startup, even if the path shown on screen is the one desired.

Choosing a machine address
While any two letter combination is valid as an address when communicating with the IC, the address WC has some important functions. I would recommend that your machine call itself "WC" in messages with the IC.

Telescope and instrument controllers interface
If desired, telescope and instrument data can be embedded in the image FITS header by enabling the appropriate options in the HAWLEY.INI file, and sending formatted strings to the IC on request.

To save telescope data:
Set TCENABLE=T in HAWLEY.INI
If your machine is called "WC" (see above), the IC will send the string IC>WC TCSTATUS before each acquisition cycle. Respond to this message with a string of the form WC>IC STATUS: keyword=value keyword=value .... The IC will append these keywords and values to the end of its FITS header after formatting them to the FITS standard.

To save instrument data:
Set IEENABLE=T in HAWLEY.INI
If your machine is called "IE" (see above), the IC will send the string IC>IE ISTATUS before each acquisition cycle. Respond to this message with a string of the form IE>IC STATUS: keyword=value keyword=value .... The IC will append these keywords and values to the end of its FITS header after formatting them to the FITS standard.

Of course, the IC does not care whether what you are sending represents telescope status, instrument status, or a grocery list. It thus provides a convenient way to get any information you may find relevant into your image headers.


Imaging Sciences Laboratory
Revised: December 18, 1997 [jam]