Known restrictions

• A motion with external measurement signal (G100) is just performed the first time. Any following backward/forward motion does not consider the external measurement signal again.
• It is not possible to move backwards over a homing command. Because this movement has external influence on axes movements (cam signal), which could not be reversed in backward direction. Even digital drives could manage the homing motion without CNC for themself. Therefore, G74 is disabled to move backwards. Any saved previous commands are rejected.
• Manual mode without parallel interpolation (G200) and manual mode with superimposed interpolation (G201) is not treated in backward/forward mode.
• Also, the motion in manual mode because of key presses and handwheel increments is not saved or reversed in backward/forward mode.
• Spindle specific commands (velocity/position) are not inverted.
• Explicit synchronization command for independent axis cannot be inverted in backward direction.
• Block search now is not considered.