UNLOCK(OPCS)             Optical Printer Control System          UNLOCK(OPCS)
        
    NAME
	unlock - (CUSTOM) unlock motors for manual adjustment
        
    USAGE
	unlock [no arguments] 
        
    DESCRIPTION
	Unlocks some or all of the motors to allow for manual adjustment.

	This command is actually a script defined with a RUNCMD(OPCSDEFS)
	command, and is normally customized by your local site engineer.

	Some sites may prefer NOT to configure this command, since the
	LOAD(OPCS) and LINEUP(OPCS) prevent the need for manual adjusting.

	This command normally does the following operations:

	    > Deenergize the motors
	    > Pause to allow user to manipulate the freewheeling axes
	    > Re-energize the motors
	    > Home them all

    INSTALLATION NOTES
	The unlock command is defined in the 'runcmd' section of OPCSDEFS.OPC:

	    runcmd unlock unlock.run 0

	..and the file 'unlock.run' would contain something like:

	    @ # Deenergize the motors. Clearing port 379 bit #7.
	    @ ldefs -c clrbit 0379 80 00
	    # *** UNSEATED FOR LOADING ***
	    @ pse -noabort
	    @ # Re-energize motors by setting the bit.
	    @ ldefs -c setbit 0379 80 00
	    @ # Home the motors we deenergized
	    @ home a b c d

        NOTE: In the older OPCS K1.xx versions 'ldefs -c' is not available,
	      so the following commands would be used instead:

			    --- OLD VERSION OF OPCS --
	    @ # Deenergize the motors. Clearing port 379 bit #7.
	    @ ! echo @ clrbit 0379 80 00 > foo.defs ! ldefs foo.defs
	    # *** UNSEATED FOR LOADING ***
	    @ pse -noabort
	    @ # Re-energize motors by setting the bit.
	    @ ! echo @ setbit 0379 80 00 > foo.defs ! ldefs foo.defs
	    @ # Home the motors we deenergized
	    @ home a b c d

	Note use of leading '@' signs to disable echoing of the commands,
	to avoid cluttering the screen with unwanted text.

        ANSI characters can be added to the script to embolden messages,
	and erase them when the user hits a key to continue.

    ORIGIN
	Gregory Ercolano, Los Feliz California 04/12/98