OPCSDEFS(DOCS)  Optical Printer Control System      OPCSDEFS(DOCS)

    NAME
        opcsdefs - OPCS definition file format description

    DESCRIPTION
        When the opcs program is started, the 'OPCSDEFS.OPC' is loaded.

        This file contains commands that sets the motor and ramp speeds,
        channel names, custom commands, interpolation curves, etc.

        After startup, the LDEFS(OPCS) command can be used to load
        different files containing other OPCSDEFS commands, allowing
        users to switch to different configurations, such as switching
        from IMAX to 35MM shooting, or changing around a filter wheel
        configuration, loading different follow focus files, fader
        curves, etc.

        The commands in OPCSDEFS files are different from the OPCS(OPCS)
        commands, and even when names are similar between them (e.g. 'reset'),
        their usage and context may be quite different, such as the
        case with SPD(OPCS) vs. SPD(OPCSDEFS).

    FILE FORMAT
        Custom files with OPCSDEFS commands should use the extension ".def",
        so as to be different from files with OPCS commands which use ".run".

        Lines starting with '#' and blank lines are ignored.
        Comments can also appear after commands, e.g.

            ramp a 10 150 15 200   # 'A' channel ramps

        Leading/trailing white space in generally ignored, so you can indent
        commands for formatting.

        Multiple commands can be stacked on a line if it serves readability, e.g.

            # BUCKLE SENSING PORTS
            buckle a 0000 00 00     buckle e 0000 00 00     buckle i 0000 00 00
            buckle b 0000 00 00     buckle f 0000 00 00     buckle j 0000 00 00
            buckle c 0000 00 00     buckle g 0000 00 00     buckle k 0000 00 00
            buckle d 0000 00 00     buckle h 0000 00 00     buckle l 0000 00 00

        ..but /generally/ there should be only one command per line.

        Commands that start with "!" will be execute as DOS commands.

        OPCS commands can be run from within an OPCSDEFS file using
        OPCSCMD(OPCSDEFS), e.g.

            opcscmd cam 12         # run the camera 12 frames
            opcscmd go d -1000     # move the fader -1000 pulses

        OPCSDEFS files can load other OPCSDEFS files with e.g.

            opcscmd ldefs otherfile.defs

    DOCUMENTATION
        Use man -k OPCSDEFS: for a full list of the OPCSDEFS commands.
        With this list, you should be able to zero in on specific commands
        using man [command].

    TRICKS WITH DEFS FILES
        People familiar with DOS will be familiar with these tricks:

        First, note that in K2.00 (and up), 'ldefs -c' can be used to run
        OPCSDEFS commands inside OPCS, e.g.:

            ldefs -c bigcounters on   # big counters

        Which makes many of the below techniques unnecessary extra work.
        However, in the older releases (K1.xx) these are unavailable,
	so the below techniques must be used.
            
        As with all DEFS file commands, you can execute motor definition
        commands from within the OPCS software by creating a small file,
        and the loading commands from it via LDEFS(OPCS)... In the following
        example, we switch back and forth between large and small counters:

            ! echo bigcounters on  > tmpfile ! ldefs tmpfile   # big counters
            ! echo bigcounters off > tmpfile ! ldefs tmpfile   # small counters

        This 'trick' can be used with any OPCSDEFS commands, and uses the 
        operating system's ECHO command and 'reroute output' symbol (>) to 
        create the file FOO, which is then loaded as a file with the LDEFS 
        command. This technique CAN be used within a script or when entering
        commands manually.

        You can create multiline files from within a script as shown in this
        example using MSDOS's > and >> (append) symbols:

            ! echo flog 2.0         > tmpfile
            ! echo logcounters yes >> tmpfile
            ldefs  tmpfile

        This technique can be programmed into run scripts, so defs file
        information can be changed on the fly.

        Here is another way to enter DEFS commands directly to the LDEFS 
        command from within the OPCS software:

            ldefs con            # Load the special MSDOS file CON...
            logcounters no       # which is really the keyboard (console)
            ppr a 400            # reading these commands from keyboard
            ^Z                   # CTRL-Z and RETURN ends this mode..
            cam 12               # ..back to OPCS commands

        The 'ldefs con' technique works well for interactive typing, but 
        cannot be programmed into a script, since it always reads from
        the keyboard. Use the 'echo' technique listed in the previous example
        for programming DEFS commands into a running script.

        These techniques are actually standard ways of using the DOS operating
        system, and are not particular to just the OPCS software. They can be
        used by any program running under MSDOS that properly supports the
        operating system.

        Users not familiar with these techniques should learn them only if they
	think they might need them. At very least, operators should be aware
	of these capabilities.

    FILES
        \USR\BIN\OPCS.EXE       - the OPCS system software executable
        OPCSDEFS.OPC            - the 'start up' definition file
        *.DEF                   - other opcs definition files
        *.RUN                   - run scripts
        \USR\CATMAN\OPCS\*      - online documentation pages

    SEE ALSO
        OPCS(DOCS)         - the opcs system in general overview
        OPCSHARDWARE(DOCS) - hardware specifics (wiring, etc)
        OPCSIFACE(DOCS)    - OPCS interface boards (A800, PIO-100, SD-800..)

    ORIGIN
        Gregory Ercolano, Los Feliz California 11/29/89