CHECK(OPCS)             Optical Printer Control System          CHECK(OPCS)

    NAME
        check  - check counter values for specific channels

    USAGE
        check <chans> <val[,val..]>

        Where:
            <chans> is either a single channel letter, or a list of
	            channel letters with no spaces, e.g. "abcd"
            <val[,val..]> is either a single value, or a comma separated
                    list of counter values, one for every channel in <chans>

    EXAMPLES
        check f 1000        -- check f channel's counter is 1000
        check fg 1000,2000  -- check f counter is 1000 and g is 2000

    DESCRIPTION
        "check" verifies counter values are where they should be.
	Useful in RUN(OPCS) scripts to help catch errors during in script
	programming and shooting.
        
        If a check fails, an error warns of the discrepancy, prompting
	the operator with an ABORT/CONTINUE option.

        It's expected that for each of the <chans> specified, the exact same
	number of counter values are specified in the comma separated <val>
	list that follows.

        Counter values must be comma delimited, and can either be numeric,
        math expressions, or feet/frame format. Example:

            check ab (150-10),13'4   -- check if a's counter is 140
                                        and   if b's counter is 13'4

            check a (pro)            -- check if counter for aerial (a)
                                        has the same value as main (pro)

            check ab (cam+5),(cam+5) -- check if aerial (a) and main (b)
                                        counters are the same as cam's

        Note in OPCS the 'a' channel is the aerial projector, 'b' is the
        main projector, 'c' is camera, and 'd' is the fader shutter. Other
	channel assignments depend on your local configuration.

    HISTORY
        Early OPCS versions only managed cam/pro/shu, so CHK(OPCS) was designed
        for that. Motion control channels were later added, so the newer
	CHECK(OPCS) was added, allowing *any* motor channel to be checked.
	CHK(OPCS) is kept for backwards compatibility.

    SEE ALSO
        CHK(OPCS)    - older command that only checks frame counters and fader
        RUN(OPCS)    - run an OPCS script file
        MOTORS(OPCS) - enable/disable motors for debugging scripts

    ORIGIN
        Gregory Ercolano, Altadena California 05/28/20