Siemens SINUMERIK 840D sl Function Manual page 437

The signal only has an effect on the following spindle.
Note
In the following cases, signal DB31, ... DBX31.6 (track synchronism) is ignored:
● Axis/spindle disable is active (DB31, ... DBX1.3 = 1).
● Program test is selected.
● SERUPRO is active.
If one of these situations arises when the "track the deviation from synchronism" function is
already active, the function will be deactivated.
Time when measurement is performed
The time when the measurement is performed and the correction value is calculated depends
on the bit 7 setting made in the following item of machine data:
MD30455 $MA_MISC_FUNCTION_MASK (axis functions)
Bit
7
Note
If a temporal extension is taken into account when relieving the tension between the leading
and the following spindle, bit 7 should be set to 0. The interface signal is then state-controlled.
The time required to relieve the tension can depend on various factors (e.g. K
control, accelerating power of the motors) and must be determined by way of experiment.
Measuring sequence
The NC/PLC interface signal DB31, ... DBX31.6 (track synchronism) can only become effective
once setpoint synchronism has been achieved:
DB31, ... DBX99.4 (synchronization running) = 0
The actual values of the following spindle are read within the interpolation cycle and the
difference between them and the setpoint position is calculated, either for as long as signal
DB31, ... DBX31.6 is activated, or just once on that signal's rising edge (the frequency will
depend on the setting of bit 7 in MD30455; see the section titled "Time when measurement is
performed").
The correction value is the difference between the setpoint and actual-value synchronism
positions. This value is saved for the corresponding following spindle in the following system
variable:
Special functions
Function Manual, 01/2015, 6FC5397-2BP40-5BA2
Value Meaning
0 The correction value is calculated continuously, as long as the NC/PLC interface signal
DB31, ... DBX31.6 (track synchronism) is set and setpoint synchronism is active (cyclic
calculation).
1 The correction value is only calculated at the time when the NC/PLC interface signal
DB31, ... DBX31.6 (track synchronism) changes from 0 to 1 (edge evaluation).
M3: Coupled axes
8.5 Generic coupling
factor of position
V
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