Workpiece Measuring; Input Values - Siemens SINUMERIK 840D sl Function Manual

M5: Measuring
8.4 Setting zeros, workpiece measuring and tool measuring
8.4.2

Workpiece measuring

Workpiece measuring
For workpiece measurement, a probe is moved up to the clamped workpiece in the same
way as a tool. Due to the variety of different measuring types available, the most common
measurement jobs can be performed quite simply and easily on a turning or milling machine.
The position of the workpiece can be measured in relation to an edge, a corner or a hole.
To determine the zero position of the workpiece (workpiece zero W) or a hole, setpoint
positions can be added to the measured positions in the WCS. The resulting offsets can be
entered in a selected frame.
Variable interface
The variable interface comprises several system variables,
These are categorized as either:
● Input values
● Output values
References:
/PGA1/ Parameter Manual System Variables
Input values must be written by the HMI or the cycles. The output values result from the
calculations.
References:
/BNM/ Measuring Cycles Programming Manual
8.4.2.1

Input values

Validity bits for the measurement types
To define which system variables are valid for the current measurement, each measuring
process must first declare all the variables as invalid. This is done with:
$AC_MEAS_VALID = 0.
Each input variable implicitly sets the corresponding bit in $AC_MEAS_VALID when writing
to the interface. If the validity bits are not reset, the values remain valid for the next
calculation.
Note
The interface is not reset in case of machine control table reset or after M30 (reset at
program end).
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Function Manual, 09/2009, 6FC5397-1BP20-0BA0
Extended Functions