Distance control states and transitions

Alternative commanding via PLC interface

In addition to the NC program, distance control can also be commanded via the PLC interface (see [HLI]) by specifying the required status transitions (e.g. activating or deactivating) and set positions via the DistanceControl control unit. The prerequisite is that distance control is activated for the axis (see P-AXIS-00328).

The status of distance control can be viewed in the status of the DistanceControlcontrol unit. The control unit's status also includes the current actual position of the workpiece surface and the currently output position offset.

Distance control has five internal states, which are shown in Figure 1-9 together with the permissible transitions. Transitions shown with a dashed line, for example a transition to the error state, take place automatically and cannot be commanded.

Distance control states and transitions 1: — Figure 1-9: Distance control state graph and transitions

The following tables contain a detailed description of the states and possible transitions.

Table 1-1: Distance control states
State	Meaning
HLI_DIST_CTRL_STATE_INACTIVE	Distance control is deactivated. The output offset (ActualOffset) is zero.
HLI_DIST_CTRL_STATE_TURNING_OFF	Distance control has been deactivated. The currently active offset (ActualOffset) is moved to. As soon as it is zero, the program switches automatically to the INACTIVE state.
HLI_DIST_CTRL_STATE_FREEZE	Distance control is active. The offset (ActualOffset) is frozen, i.e. the axis is not adjusted to the workpiece surface.
HLI_DIST_CTRL_STATE_ACTIVE	Distance control is active and adjusts the axis to the workpiece surface.
HLI_DIST_CTRL_STATE_ERROR	Distance control is in the error state, e.g. due to an incorrect state transition or due to an error in the position controller. Only a transition to TURNING OFF is possible out of this state.

Table 1-2: Permissible transitions
Transition	Meaning
HLI_DIST_CTRL_ON	Distance control is activated. On activation, a set position for the workpiece surface must be passed on. If no absolute position sensor is used, distance control must be referenced beforehand.
HLI_DIST_CTRL_OFF	Distance control is deactivated. The program switches to the TURNING OFF state, in which the position offset is travelled out. The program then switches automatically to the INACTIVE state.
HLI_DIST_CTRL_FREEZE	The current position offset is frozen. Adjustment of the axis to the actual workpiece surface is ended.
HLI_DIST_CTRL_REF	Referencing of distance control if no absolute position sensor is used. Referencing is allowed only in the INACTIVE state. A reference position must also be passed on for this transition.