Siemens 840D probing-x, probing-y change

[Anonymous]

The Siemens 840D post processor outputs a Cycle978 for single point probing X, Y, or Z. And in the case of X or Y, there is supposed to be a parameter called _MD that outputs a 1 if the measuring axis is supposed to move positive, or a 2 if it is supposed to move negative. This parameter and logic isn't in the post, and I'm wondering how to write the logic to determine positive or negative movement.

[makko74]

Hi,

the Parameter _MD is not necessary in this case. This is handled by setting the _SETVAL Parameter ( there is also handled the logic for - or + direction ).

Example measuring X direction: start postition for measuring is X-10Y?, _SETVAL=0 ( target position ). Why the cycle should move in X minus, when the target position is in plus direction from start postion?

The cycle knows its position and the position to be measured and thus the direction in which it has to go.