Siemens SINUMERIK 840D sl Function Manual page 123

Setpoint synchronization
NC-specific machine data
Number Identifier $MN_
MD18720 MM_SERVO_FIFO_SIZE
Note
With the simultaneous use of lead link axes and cross-NCU axis containers, the axis container
means machine data MD18720 $MN_MM_SERVO_FIFO_SIZE = 3 must be set. This means
a synchronous output of the setpoints for leading and following axis is not possible. The offset
then has the size of one interpolator cycle.
Leading, lead-link and following axis
NC-specific machine data
Number Identifier $MN_
MD10000 AXCONF_MACHAX_NAME_TAB
MD10002 AXCONF_LOGIC_MACHAX_TAB
Channel-specific machine data
Number Identifier $MC_
MD20070 AXCONF_MACHAX_USED
Axis-specific machine data
Number Identifier $MA_
MD30554 AXCONF_ASSIGN_MASTER_NCU
Extended Functions
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
Meaning
Size of the IPO/SERVO data buffer
The transfer of the setpoints of the leading axis via the NCU link to the
NCU of the lead-link axis produces a deadtime of two interpolator cycles.
The dead time is compensated by parameterizing the sizes of the IPO/
SERVO data buffer on the NCU of the leading axis and the NCU of the
lead-link axis:
● NCU of the leading axis: 4
● NCU of the lead-link axis: 2
Meaning
Machine axis name
Logical machine axis image
Meaning
Used machine axis
Meaning
Master NCU
If a machine axis can be traversed for several NCUs, one NCU must
be defined as master NCU. The setpoint generation is made after the
startup of the control for this NCU.
B3: Distributed systems - 840D sl only
3.2 NCU link
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