Measurement methods (P-AXIS-00516)
P-AXIS-00516 | Measurement methods | |
Description | The parameter defines the source of the probing signal during a measuring travel, e.g. the probing position can be latched in the drive or the probing signal can be provided by the PLC. The measuring signal source can also be changed in the NC program with the #MEAS command (see [PROG//Extended programming] can also be changed in the NC program.
This parameter replaces the following old configuration parameters:
| |
Parameter | kenngr.measure.signal | |
Data type | STRING | |
Data range | DRIVE_TYPE_DEFAULT PLC FIXED_STOP DRIVE PLC_EXT_LATCH_CONTROL PLC_FIRST_EVENT PLC_TIMESTAMP | |
Axis types | T, R, S | |
Dimension | T: ---- | R,S: ---- |
Default value | * | |
Drive types | ---- | |
Remarks | For backward compatibility reasons, the settings resulting from the old parameters are used if the parameter P-AXIS-00516 is not defined. * Note: The default value of variables is a blank string. | |
The meaning of the parameter settings is described in the following table:
Value | Meaning |
DRIVE_TYPE_DEFAULT | The CNC uses the default measuring method of the given drive type (see table below /*/) |
PLC | This parameter setting reads the probing signal via the Control Unit PLC parameters on the HLI [HLI]. The probing value is the actual value at the moment of the occurrence of the probing signal. As an alternative, the probing position can be specified directly via the control unit Axis control commands.
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 the measuring traverse. In addition, the measurement type 7 (see P-CHAN-00057) must be selected.
CAUTION: The user has to ensure that, during the movement to a fixed stop in the drives affected, a torque limitation is active and that the velocity 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 an external hardware for the measurement travel. Therefore the CNC informs the PLC via the external measuring interface about the start and end of a measuring travel so that the PLC can enable or disable the measurement hardware accordingly (see [HLI//Measuring with external probing hardware]). This method specifies the probing signal and the measured position via the control units PLC parameters and Axis control commands. |
PLC_FIRST_EVENT | This setting corresponds to the value “PLC“. However, the measuring travel stops as soon as the measurement event is detected at an axis measured with this setting. In “PLC mode, however, a measurement event must occur in the control unit PLC parameters at every measured axis. This setting corresponds to the old parameter kenngr.mess_signal_achs_steuer (P-AXIS-00115) |
/*/ Drive type dependent default setting for probing signal source (DRIVE_TYPE_DEFAULT ):
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 |
Permissible measurement methods dependent on drive type:
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 fieldbus (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 |
(*) Using the measurement simulation (see P-AXIS-00112, [PROG//Extended programming])