BAIT: ccd protocol

CCD protocol

Below is a general description of the typical commands using the BAIT communication protocol and replies given by Charge Coupled Devices and other imaging devices.

DESCRIPTION

ccd [time=%f] [dark] [noread] [nbytes=%d] [file=%s] [display] [init] [gain=]

Opens the CCD shutter for the number of seconds specified by the time= keyword. It will wait for the exposure to end. The shutter will not open if the `dark' flag is used, but will wait for the exposure time specified. (This is used for DARK frames.) Usually the CCD is readout after an exposure, the readout can be skipped if the `noread' flag is used. The command returns the string `actual=xx.x' where xx.x is the actual value of the exposure time. This number will differ by an amount depending on the resolution of the shutter timing circuit. See the ccd_status command.

The `display' keyword causes the most recent image to be displayed on the ccd controller console using autoscaling. This is currently a no-op for the Macintosh version.

The init command initializes the state of the CCD controller. It may be a no-op.

ccd_status

Returns the string:


done ccd_status darktime=89 nrow=512 ncol=512 tchip=-45 readtime=20 name=TH7895 gain=1 pix=19 rot=45.0

Darktime is the number of seconds since (the start of) the last readout. The number of rows and columns is the chip size (it should agree with the value in ait.config). The chip temperature is in degrees Celsius. The readtime is how long it should take to read the chip into memory. The pixel size is in microns. The chip rotation is in degrees.

ccd_eraselog

Erases the log file kept on the CCD computer. If not erased periodically, it can grow to multi-megabyte size in a few nights and fill the disk.

Protocol Index | BAIT Index

Last Revised July 5, 1999