Basic Scanner's Guide

{The Bottom Line: See "About build 2.3 and how it is different".}

This document gives instructions for production scanning. For instructions on research scans, changing defaults, or for more detailed "behind the cookbook" information, see the Advanced Scanner's Guide .
A sample session is located in IBASE:[SUPERTASKS.ALIA.JOURNAL]BUILD2_1.SAMPLE.

Contents:

Getting started: what to put in your login.com
How to start a production scan
Starting from scratch: after a reboot or logoff
Useful commands
About build 2.3 & how it is different
What's coming next

Getting started:

Edit your login.com file, and put the following lines in it:

           $ @alia_com:define_commands	!defines alia/sac/babyscan stuff   
           $ @base:[control]define_idl_commands		!defines idl stuff

Once you've put these in your login.com (and executed it in any existing windows), you will have a number of useful commands defined. You must have these commands defined for the remaining instructions to work.
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How to start a production scan with ALIA Build 2.3

For a normal production scan
Type SCAN .
You will be prompted for the scan disk and filename to use. If it has a standard filename and the filename indicates it is a 1mm plate, you'll also be prompted to measure the upper focus in the center of the plate, and then instructed how to set the upper and lower focus dials. You'll be prompted for the photometric setup values that you used to enter in the TP_NML file. You will be given the option to set the fiducial, and measure the fat zero.
For a plate that you need to do extensive focus tests on
In another window, invoke IDL and run the extensive focus tests to determine the appropriate focus settings.
Then, in the ALIA window, type SCAN/SET_FOCUS or, SCAN/FOCUS=ADHOC . You will be prompted to enter the focus settings that you determined with the IDL focus test. Everything else will be the same.
For a flat plate
Type SCAN/FOCUS=FLAT .
You'll be instructed how to set the lower focus, and prompted to enter the setting for the upper focus. Everything else will be the same.
Note that if you are doing a production scan of an ER plate, you don't need to say SCAN/FOCUS=FLAT . The fact that the filename will start with the letters ER will tell ALIA that it is a flat plate.

Cookbook for starting from scratch after a reboot or logoff

Log onto the computer with at least 1 window.
Type SET PROC/PRIV=(GROUP,SHARE)
Type START_SAC to start the stand alone console
Then do $ SCAN Note that it does not matter where you type SCAN from.

Special note for reboots caused by powerdown

If the SAC comes up, shows the "Booting" message, but then goes down again (leaving the displays apparently frozen), examine the file ALIA_DATA:SAC.LOG. If it contains messages such as "ack, qio error occurred", then there may be an initialization problem with the Micro488a controller (the little black box that interfaces between TTA2 and the servo box).

To remedy this, get into hw_idl and type ieee_init . This should clear the abnormal condition of the controller. When it completes, try START_SAC again.

[The following is no longer needed for routine scanning, but is included here for reference.]

To get baby_scan idl, do the following:

              $	BABY_SCAN_PLACE
              $	SETUP_HW_IDL
              $	IDL HW_IDL
              >

Useful commands

IDL related:

setup_hw_idl: sets things up so you can type idl hw_idl, and get the hw_idl environment (like for babyscan)
setup_spam: sets things up so you can type widl, and get spam.
Note, these are somewhat incompatible. You can't just execute them both in advance and then have idl hw_idl mean one thing, and widl the other thing. Someday we hope to fix this.
baby_scan_place: sets your default to the directory containing the baby_scan and focus stuff.

SAC related:

start_sac: starts the SAC as a detached process
stop_sac: brings the SAC completely down
sleep: puts the SAC into hibernation
wake: wakes the SAC up from hibernation
command_sac or sac_menu: gives you a menu-driven program that you can use to command the SAC to do things like drive to a specific position, reset devices, etc.
check_sac: reports the current state of the SAC process, and suggests what to do if you are having a problem
fill_servo or fill_servo_coeffs: instructs the SAC to initialize the servo (and other devices) with the standard set of servo coefficients - for example, to clean up after engineering tests

Scan related:

blue_button or pause

pause a scan so you can go in the room, turn on the light, etc

scan

start a standard production scan, complete with shading & spot scans. Prompts for directory & filename.

select_scan

This verb makes performance of only parts of the "standard production scan" much easier. It lets the user choose to perform any or all of the following:

Focus & photometric setup
Shading scan
Spot scan
Main scan

It handles all necessary file cleanup in the case of, eg, needing to restart a scan after focus & photometry information has already been recorded. It is also useful for testing. Use this command if you need to restart a scan that died after successfully doing focus, shading, or spot scans.

spot_scan

(Not presently available.) start a spot scan. Prompts for directory & filename. Omits shading scan and photometric setup.

research_scan

do a nonstandard scan. Prompts for task parameter file (which contains the instructions for the nonstandard scan), directory, & filename.

5. About ALIA Build 2.3

Build 2.3 introduces a simple form of error recovery for the first time. Essentially, when an error is detected, all ALIA processes stop what they are doing, go back to the beginning of the pass, and try again. If there are too many errors on a given pass, the program will declare defeat.

If any errors occur during a scan, the time and location of the errors is recorded in a rrrrr_pppp_nn.ERRORS file on the scan disk. Furthermore, a mail message is sent to the distribution contained in alia_data:error_scan.dis, advising that errors have occurred and careful visual qa should be performed on those regions.

It also includes a few other items:

Disarms the shutter during scan setup procedures. This means the shutter is on a 30 minute timer. (During a scan, it is on a 30 second timer.)
Offers the option to abort after a shading scan if the shading coefficients were unacceptable.
Includes the new task parameter sw_max_retries_per_pass, used to determine how many times to retry on a given pass before giving up.

What's coming next

We're still not sure, but present inclinations are to implement the ability to do single channel scans, to make doing some engineering tests easier. The next build may also include a pre-scan database check.
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Vicki Laidler -- laidler@stsci.edu
Last updated 12/7/95