CHK(OPCS)		Optical Printer Control System		CHK(OPCS)

    NAME
	chk  - check if the pro/cam/fader counters are at certain values

    USAGE
	chk  [pro] [cam] [fader]            # single head printer
	chk  [pro2] [pro1] [cam] [fader]    # dual headed printer

    EXAMPLES
	chk  10  13'12  0
	     |     |    |
	     |     |    Check if fader is closed
	     |     Check if camera counter reads 13 feet 12 frames
	     Check if projector counter reads '10'

    DESCRIPTION
        This command helps verify counter values are where they should be
        in RUN(OPCS) scripts.

        It lets the author check to see if the specified channels' counters
        are what the author expected them to be.  This helps catch errors
        during script programming + shooting.
	
	If a comparison fails, an appropriate error warns of the discrepancy,
	and prompts the operator with an ABORT/CONTINUE option.

	Arguments can be either in frames or in feet/frames format.
	Arguments can be '-' to skip comparison checks for a motor, example:

	    chk - - 170       # only check if fader at 170 degrees
	    chk 120 - - -     # only check if pro2 counter reads 120

    EXAMPLE
        Assuming the counters read: PRO=34, CAM=12, SHU=0, and the following 
	command is executed from a running script:

	    chk 34 10 170

	...all running scripts will be stopped, and the following errors will 
	be generated (because the camera and fader are not in the positions
	that were specified):

	    CHK:  Camera not at 10 frames
	    CHK:  Fader not at 170 degrees
	    Hit any key to continue  (ALLSTOP TO ABORT)

    HISTORY
        Early OPCS versions only managed cam/pro/shu, so CHK(OPCS) was designed
        for that. Motion control channels were later added, the newer CHECK(OPCS)
        was added, allowing *any* motor channel to be checked. CHK(OPCS) is kept
        for backwards compatibility, and syntactically simpler to use.
♀
    SEE ALSO
        CHECK(OPCS)    - newer command that can check all counters
	RUN(OPCS)      - run an OPCS script file
	MOTORS(OPCS)   - enable/disable motors for debugging scripts

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