IMOV doing strange stuff

    I'm going to contact local support next week, but I want to know if any of you has encountered this behavior.

    It's a NX100. I made a macro to do offsets and it works except when one coordinate of the offset position variable is set within a random range. If the coordinate is in this range, the fifth axis starts to move - even though its offset coordinate is 0,000.

    Macro code

    Calling job code

    Code
    OFFSET 0 0 -1700000 0 0 0 500

    If I set the Z around that mark the V axis starts to rotate halfway through the trajectory. I don't know how much it tries to move since the robot will collide if I continue, but it goes one degree up each second. The starting and ending position are safely inside the robot range though.

    What's making me go crazy is that I can move the Z manually all the way down no problemo; the offset WORKS by testing INTERLOCK+FWD, the offset FAILS by INTERLOCK+TEST START, and the offset WORKS in both if the value is LESS or GREATER than -1700,000.

    I thought maybe it had to do with the macro, so I put the code in the job - nothing. Maybe it's the variables, overflowing or something that's not giving an alarm, so I got rid of them and set a constant in the SETE command - nothing. I checked the local position variable being built - it's correct. What's going on here? How can it work in FWD and not TEST START? Is it a bug in the interpolator program?

    Code
    X:    0.000
Y:    0.000
Z:    -1700.000
U:    0.000
V:    0.000
W:    0.000
COORD:    BASE

    No, they are all in the same coordinate system. As a matter of fact I made a new program with recorded points - no macros or realtime calculated positions - and it displays the same behavior.

    I sent a video to support and they said it's singularities. Even though I don't see them myself - the joints aren't aligned at cero and the arm is not twisted nor twists in any way, and it goes up and down in manual just fine. But they said it's normal that it only shows in auto mode (I did not know this). Though I'm still scratching my head over why it only does it when reaching just slightly above or below the original point, as the trajectories are identical. Or when it goes up but not down, the path being the same.

    I will upload the video in the next days

    I would guess singularity also. There aren't too many Yaskawa 6-axis robots with the reach to move 1.7 meters in Z without going through singularity.

    The FWD key ignores program speed and uses the manual jogging speed. L, M, H. How fast these are is set in parameters. Interlock+Test Start uses program speed up to 25% of maximum speed. Play (ignoring all the other factors) runs at program speeds.

    You can see problems in teach where a motor is running too slowly but not in play, because the motor is allowed to run faster. You can see problems in play because the motor can run faster but not in teach where the motor speed is limited, or both in teach and play.

    I know a thing or two, because I’ve seen a thing or two. Don't even ask about a third thing. I won't know it.

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