What I gather from Fanuc manuals, the minimum slide movement in increment system B is 0.0001 inch (which is called least command increment) on an inch machine. This is equal to 0.0025 mm. Now, when we work in G21 mode, how can an accuracy of 0.001 mm be maintained? In other words, G21 G91 G00 X0.001 will not cause any actual movement.
Either accept this statement or please contradict me. Either way, I would learn something.