G28 Reference Point Return
G28 reference point return G-code is used to approach the reference point via an intermediate position.
The intermediate position can be specified absolute X, Z or relative U, W.
What is reference point read CNC Zero Return or Reference Point Return
During G28 reference point return command machine,
first reaches intermediate-point rapidly (G00),
then it moves rapidly to reference-point position.
G28 X(U) Z(W)
X, Z absolute intermediate point position.
U, W incremental intermediate point position.
For following exmaples suppos actual referece-point position on your machine is X330 and Z529.
G28 U0 W0
the machine will directly move to reference-point (as no intermediate point is given).
G28 X100 Z100
the machine will first move to intermediate position X100 Z100
and then will move to reference-point.