Siemens SINUMERIK 840D sl Function Manual page 390

K3: Compensation
5.4 Interpolatory compensation
This way AX3 on NCU-1 is "coupled" with AX2 on NCU-2 (see configuration 1).
The following variants can be used to parameterize if the axes to be coupled are on different
channels:
● Version 1: "Programming with channel axis identifier":
● Version 2: "Programming with machine axis identifier":
Assignment of the axes
The assignment of the input and output axes is done via the following system variables:
$AN_CEC_INPUT_NCU
$AN_CEC_OUTPUT_NCU
The system variables become effective only after a restart.
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Two different part programs TP1 and TP2 are created, they are then processed in
different channels.
Axis "ZZ" is coupled to "XR":
View from the part program TP1 in Channel 1:
$AN_CEC_INPUT_AXIS[0] = (XR)
View from the part program TP2 in Channel 2:
$AN_CEC_OUTPUT_AXIS[0] = (ZZ)
Axis AX2 on NCU2 is coupled with Axis AX1 on NCU1 upon restart after TP1 is executed
in Channel 1 and TP2 is executed in Channel 2.
One part program is created that runs in any convenient channel of NCU1 and specifies
the machine axis names together with the NCU numbers.
Axis "ZZ" is coupled to "XR":
$AN_CEC_INPUT_NCU[0]=1
$AN_CEC_INPUT_AXIS[0] = (AX1)
$AN_CEC_OUTPUT_NCU[0]=2
$AN_CEC_OUTPUT_AXIS[0] = (AX2)
The NCK monitors whether the axes on the local NCU have actually been interpolated,
i.e., there is a channel that can program these axes. The local NCU is always the NCU on
which the part program runs.
The following axes are allowed for NCU1 as input or output axes in Configuration
1: NC1_AX1, NC1_AX3, NC1_AX4, NC1_AX5, NC2_AX2, NC2_AX6
The data backup from the NCK always delivers the compensation data from the "machine
axis indentifier" view.
NOTICE
The NCU no. is to be programmed before the axis identifier. A sag compensation
between NC1_AX1 and NC1_AX2 is not possible.
and $AN_CEC_INPUT_AXIS
and $AN_CEC_OUTPUT_AXIS
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
Extended Functions