Measure with external measuring hardware

Basics

If the control of an external measuring hardware required for the measurement run, the external measurement interface between the CNC and the PLC can be used. The CNC informs the PLC of the start and end of a measurement run so that the PLC can enable and disable the measuring hardware accordingly.

CNC – SPS

At the start of a measurement run, the CNC writes the task ‘Enable probe” containing the required parameter number of the probing input and the relevant edge in the task ‘Enable probe” and sets X_Please = TRUE.

After reading (X_Please = FALSE) and enabling the measuring hardware, the PLC acknowledges the task with X_Done = TRUE). Accordingly, if the position latch is successful or aborted, the CNC signals the end of the measurement run with a CNC reset. Please note that the PLC must always acknowledge these tasks.

For more information on the interface structure, refer to the HLI documentation ([HLI]).

After the measurement event occurs, the PLC writes the detected probing position to the control unit MCControlSGN32Unit_ProbingPosition and then signals the measurement event to the control unit MCControlBoolUnit_ProbingSignal (see [HLI//Control commands of an axis]).

Notice

When the external measuring interface is used, the probing signal of the control unit MCControlBoolUnit_ProbingSignal is not dependent on the relevant measuring edge P-AXIS-00518. A positive edge always signals the successful detection of a measured value in the external measuring hardware.

Notice

If the control unit MCControlSGN32Unit_ProbingPosition is not enabled when the measurement event occurs, the actual value at the time of the probing signal occurrence is used.

Axis parameters

The following axis parameters are required for measuring with the CNC-PLC interface:

Alternatively, the measuring interface can also be enabled in the NC program by the #MEAS command (see [PROG//Extended programming]).