This is an internal command. It communicates any necessary option bits and readout parameters to the controller. It is automatically run as the first step of a ``go'' command.
This is an internal command. Normally in observing mode the detector is in a constant cleaning mode called ``sweeping.'' If this sweeping mode has not flushed the detector at least once, a ``clean'' runs automatically as the second step of a ``go'' command.
This is an internal command. It performs the integration step and returns when integration is complete if typed with no parameters. The form ``expose auto'' is the third step of a ``go'' command. In this form, its behavior is dependent on whether ``expose fg'' or ``expose bg'' mode is active. The default mode is ``expose fg'' in which case ``expose auto'' is identical to ``expose'' and returns when integration is complete. If ``expose bg'' has been issued, however, then ``expose auto'' returns when integration starts so that other commands can be issued to Director which will overlap with the exposure step. Once such an exposure is started, ``expose wait'' can be used to perform a blocking wait for the end of the exposure, but even if this is not used, detcom will proceed automatically into the readout phase when the exposure completes. The following table summarizes expose options:
|expose||Integrate and return when complete|
|expose fg||(default) Causes subsequent expose auto to behave like expose.|
|expose bg||Causes subsequent expose auto to return immediately.|
|expose auto||Begin integration. When it returns depends on fg|bg.|
|expose wait||Block until current integration (if any) is complete.|
|expose poll||Return immediately. FAIL means integration is still in progress.|
This is an internal command. It is normally triggered immediately after an ``expose auto'' by the ``go'' command (even in ``expose bg'' mode.) Depending on the setting of ``auto save'', a FITS file is usually saved to disk in parallel with the readout operation. Similar to ``expose bg|fg'', a ``readout fg'' and ``readout bg'' mode exists. If ``expose bg'' is active, ``readout bg'' is implied and the setting is irrelevant. For the normal case of ``expose fg'', however, ``readout bg'' causes a ``go'' command to return successfully at the start of the readout instead of the end. A ``readout wait'' can force a blocking wait for the end of the readout. Built-in DetCom commands that would conflict with a readout in progress already include an internal call to ``readout wait'' so it is only necessary to call ``readout wait'' explicitly before any non-detcom operation (such as slewing) if you do not wish for it to overlap with readout. Readout options are summarized in the following table:
Note that there are currently slight differences in the options between readout and expose, although the concept is the same.
This command does a blocking wait for any save-to-disk operation that might be in progress. If none is in progress, it returns immediately.