MM4039,
I think I understand your confusion about the reference point. I also suffered that same confusion. I think it might be best to imagine the G53 X0Z0 as a "derived coordinate" which has a relative offset from the G28 position. When we home the machine, it goes to the G28 position, whose display coordinates are preset in parameters. Once the G28 position is reached, this in effect defines where the G53 X0Z0 must be. That is not saying that the G53X0Z0 is at the G28 position. But it does have a well defined offset from that G28 point.
Whether the machine was ever set up correctly so that the reference tool position is correctly described in the G53 coordinate system, is what I strove to accomplish. Before I did this, the G28 coordinates on my machine were just "tape measure coordinates", not really anything to be relied upon.
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(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management) |