Measurement methods (P-AXIS-00516)

Value

Meaning

DRIVE_TYPE_DEFAULT

The CNC uses the default measuring method of the given drive type (see table below /*/)

PLC

With this parameter setting, the probing signal is read by the lr_mc_control.probing_signal control unit on the [HLI]. The probed value is the actual value at the moment when the probing signal occurred. As an alternative, the probing position can be specified explicitly by the lr_mc_control.probing_position control unit

NOTE:

Due to the scanning of the probing signal in the cycle time of the PLC, the accuracy of the probed value is less than the accuracy achieved by using drive-internal probing latches.

This setting corresponds to the old parameter kenngr.probing_signal_via_plc (P-AXIS-00257).

FIXED_STOP

This setting searches for a fixed stop during a measurement run. In addition the measuring type 7 (see P-CHAN-00057) must be selected.

CAUTION:

The user must ensure that, during the Move to fixed stop function in the drives affected, a torque limitation is active and the speed is low enough.

This setting corresponds to the old parameter kenngr.meas_signal_fixed_stop (P-AXIS-00330)

DRIVE

This parameter defines that the probing signal is supplied by the drive. Additional settings in the drive are required (see [FCT-C4]).

This setting corresponds to the old parameters kenngr.mess_signal_taster (P-AXIS-00117), kenngr.mess_signal_sercos (P-AXIS-00116), kenngr.meas_signal_drive (P-AXIS-00269)

PLC_EXT_LATCH_­CONTROL

This setting defines that operation requires external hardware for the measurement run. Therefore the CNC informs the PLC via the external measuring interface about the start and stop of a measurement run, so that the PLC can enable or disable the probing hardware accordingly (see [HLI//Measuring with external probing hardware]). This method specifies the probing signal and the probed value via the lr_mc_control.probing_signal and lr_mc_control.probing_position control units.

PLC_FIRST_EVENT

This setting corresponds to the value “PLC“. However, the measurement run terminates as soon as the measuring event is detected in one of the axes measured using this setting. On the other hand, in “PLC” mode, a measuring event must occur on each of the measured axes in the lr_mc_control.probing_signal control unit.

This setting corresponds to the old parameter mess_signal_achs_steuer (P-AXIS-00115)

PLC_EXT_LATCH_CONTROL_TIMESTAMP

This setting defines that operation requires external hardware for the measurement run. Therefore the CNC informs the PLC via the external measuring interface about the start and stop of a measurement run, so that the PLC can enable or disable the probing hardware accordingly (see [HLI//Measuring with external probing hardware]). With this method, the probing signal and the point in time are specified by the control units, PLC parameters and control commands of an axis. The CNC calculated the exact measured value at the measurement time transferred.

Drive type (see P-AXIS-00020)

Probing signal source default setting

Conventional

Sercos

Profidrive

Beckhoff Lightbus

+-10V via field bus (terminal)

RT Ethernet

CANopen

CAN bus

DRIVE

Drive simulation

Virtual axis

PLC_FIRST_EVENT

Drive type (see P-AXIS-00020)

PLC

FIXED_STOP

DRIVE

PLC_EXT_LATCH_­CONTROL

PLC_­FIRST_-EVENT

Conventional

X

X

X

X

X

Sercos

X

X

X

X

X

Profidrive

X

X

X

X

-

Beckhoff Lightbus

X

X

X

X

-

+-10V via field bus (terminal)

X

X

X

X

-

RT Ethernet

X

X

X

X

-

CANopen

X

X

X

X

-

CAN bus

X

X

X

X

-

Drive simulation

X

X

(X)*

X

X

Virtual axis

X

X

(X)*

X

X