System Variables To Enter A Leading Value; Supplementary Conditions; Example; System Of Units Within A Link Group - Siemens SINUMERIK 840D sl Function Manual

B3: Distributed systems - 840D sl only
3.2 NCU link
3.2.5.3

System variables to enter a leading value

Leading values can be specified on the NCU of the leading axis using the following system
variable:
● Position leading value: $AA_LEAD_SP[<leading axis>]
● Velocity leading value: $AA_LEAD_SV[<leading axis>]
When making a change, the values are also transferred to the NCU of the following axis per
NCU link.
Note
These system variables have a lower transfer priority than those of the link variables.
3.2.5.4

Supplementary conditions

The following supplementary conditions must be observed:
● The leading axis cannot be a link axis
● The leading axis cannot be a container axis
● The leading axis cannot be a gantry axis
● The leading axis may only be replaced within its own NCU (see Section "Axis
replacement (Page 363)")
● Couplings with lead link axes must not be cascaded
● A lead link axis must not be traversed independently of the leading axis
Note
"Lead link axes and "link axes" functions
Because the "lead link axes and "link axes" functions require different settings in machine
data: MD18720 $MN_MM_SERVO_FIFO_SIZE, they cannot be used simultaneously within
a link group.
3.2.5.5

Example

A detailed example for parameterizing and programming an axis coupling with lead-link axis
is provided in the Section: "Examples" > "Lead link axis (Page 138)".
3.2.6

System of units within a link group

For a cross-NCU interpolation, the same system of units must be active on all NCUs of the
link group.
124
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
Extended Functions