Siemens SINUMERIK 840DE sl Commissioning Manual page 1288

Tips and tricks
B.3 Tips for the CHANGE method
B.3 Tips for the CHANGE method
● Always keep CHANGE methods very short and small, particularly for those whose variables
are connected to a system or user variable and change very frequently.
Reason:
Increases the screen performance.
● If possible, do not configure any RNP() functions in CHANGE methods. Instead, it is better
to configure an invisible variable parallel to the system or user variable to be read and then
use this.
Reason:
An RNP() function would be issued with each call. Otherwise, the current value which is
already available would be simply accessed.
Example:
A name resolution is performed via RNP() for each change of the axis motion in order to
read channel-specific machine data:
DEF AXIS_POSITION_X =
CHANGE(AXIS_POSITION_X)
has moved: "
<< AXIS_POSITION_X)
END_CHANGE
Keep the channel-specific machine data up-to-date with the aid of an invisible variable, copy
each value change to a temporary variable, e.g. register.
This temporary variable can then be used in the CHANGE method of the value change for
the axis position without making a name resolution of the machine data each time and the
subsequent read access:
DEF AXIS_POSITION_X =
DEF AXIS_NAME_X = (S///,""/WR0//"$MC_AXCONF_GEOAX_NAME_TAB[0]")
CHANGE(AXIS_NAME_X)
END_CHANGE
CHANGE(AXIS_POSITION_X1)
END_CHANGE
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DLGL("Axis """ << RNP("$MC_AXCONF_GEOAX_NAME_TAB[0]") << """
REG[0] = AXIS_NAME_X
DLGL("Axis """ << REG[0] << """ has moved " << AXIS_POSITION_X)
(R///,""///"$AA_IM[X]")
(R///,""///"$AA_IM[X]")
Programming Manual, 12/2017, 6FC5397-1DP40-6BA1
SINUMERIK Integrate Run MyScreens (BE2)