Measurement methods (P-AXIS-00516)

P-AXIS-00516

Measurement methods

Description

The parameter defines the source of the measuring signal during a measuring traverse, e.g. the probing position can be latched in the drive or the measuring signal can be provided by the PLC. The measuring signal source can also be changed in the NC program with the #MEAS command (s. [PROG//Extended programming]).

 

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

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.

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

With this parameter setting, the probing signal is read from the HLI via the control unit MCControlBoolUnit_ProbingSignal [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 with the control unit MCControlSGN32Unit_ProbingPosition.

 

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 measuring type 7 (see P-CHAN-00057) must be selected.

 

ATTENTION:

The user has to ensure that, during the movement on 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 determines that the measurement signal is provided by the drive. Additional settings in the drive are necessary (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 determines that the measuring traverse requires an external hardware which has to be commanded. Therefore the CNC informs the PLC through the external measuring interface about the start and stop of the measuring process, so that the PLC can enable or disable the probing hardware accordingly (s. [HLI//Measuring with external probing hardware]). With this method the measuring signal and the measured position is provided by the PLC via the control units MCControlBoolnit_ProbingSignal and MCControlSGN32Unit_Probing- Position.

PLC_FIRST_EVENT

This setting corresponds to the value PLC. However, the measuring traverse terminates as soon as the measuring event is detected in one. By contrast, in PLC mode, each measuring axis must experience a measuring event in the control unit MCControlBoolnit_ProbingSignal.

This setting corresponds to the old parameters kenngr.mess_signal_-achs_steuer (P-AXIS-00115)

/*/ Default setting for measuring input (DRIVE_TYPE_DEFAULT ) dependent on drive type:

Drive type (see P-AXIS-00020)

Default setting for measuring input

Conventional

Sercos

Profidrive

Beckhoff Lightbus

+-10V via field bus (Terminal)

RT-Ethernet

CANopen

CAN-Bus

DRIVE

Drive Simulation

Virtual axis

PLC_FIRST_EVENT

Valid measuring inputs in dependency of 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 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

(*) With help of the measuring simulation (see P-AXIS-00112, [PROG//Extended programming])