LDEFS(OPCS)		Optical Printer Control System		LDEFS(OPCS)

    NAME
        ldefs - load a new motor definitions file

    USAGE
    	lmd [filename]

    EXAMPLES
	ldefs hicon.opc    # where hicon.def contains one or more
	                   # OPCSDEFS commands
	
    DESCRIPTION
        This command allows the operator to load other definitions files.
	Users can make copies of the OPCSDEFS.OPC file, and make changes
	to the copy, then load this new copy with the LDEFS command to put
	the changes into effect. This avoids modification of the original
	OPCSDEFS.OPC file.

	Definition files contain special commands that setup the OPCS system's
	internal parameters. Try 'man -k OPCSDEFS:' for a listing of all the 
	definition file commands that can appear in OPCSDEFS files (such as
	the startup file 'opcsdefs.opc'), or for files that can be loaded 
	with LDEFS(OPCS).

    TRICKS WITH DEFS FILES
    	People familiar with the IBM's operating system will be familiar with
	these capabilities...

	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 > foo ! ldefs foo    # use big counters
	    ! echo bigcounters off > foo ! ldefs foo   # use 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 >  foo
		! echo logcounters yes >>  foo
		ldefs  foo

	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 this capability.

    SEE ALSO
       ECHO(OPCSDEFS) - disable echoing of defs commands
       OPCSCMD(OPCS) - run OPCS commands from within the OPCSDEFS command mode
       man -k OPCSDEFS: - list OPCSDEFS commands with 'one liner' descripitions
       man -k OPCS:     - list OPCS commands with 'one liner' descriptions

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

© Copyright 1997 Greg Ercolano. All rights reserved.