Commissioning - Siemens SINUMERIK 808D Function Manual

negative traversing direction. The deviation at the particular compensation point is entered as difference between the ideal
setpoint and measured actual value in the compensation tables. The control automatically calculates compensation values
of intermediate values using linear interpolation.
Preconditions / activation
The "direction-dependent LEC" function does not become active until the following conditions are fulfilled:
● The function has been activated for the relevant machine axis (compensation axis):
MD32710 $MA_CEC_ENABLE[<AXi>] = 1
● The compensation values are stored in the static user memory and are active (after POWER ON).
● Evaluation of the relevant compensation table has been enabled:
SD41300 $SN_CEC_TABLE _ENABLE[<t>] = 1
● The current measuring system of the base and compensation axes has been referenced:
DB31, ... DBX60.4 or 60.5 =1 (referenced/synchronized 1 or 2)
As soon as these conditions have been fulfilled the setpoint position of the compensation axis is altered in all modes with
reference to the setpoint position of the base axis and the corresponding compensation value and is then immediately
traversed by the machine axis.
If the reference is then lost, e.g. because the encoder frequency has been exceeded (DB31, ... DBX60.4 or 60.5 = 0),
compensation processing is deactivated.
The activation of the compensation can be checked using a reference measurement, e.g. using the laser interferometer or in
the simplest case, using the service display of the particular axis.
11.3.4.2

Commissioning

Measuring the error or compensation values
When commissioning the "direction-dependent LEC" - just the same as when commissioning the "unidirectional LEC" -
direction-dependent error curves for each axis are determined using a suitable measuring device (e.g. laser interferometer).
A part program with measurement points and wait times should be generated in order to perform the measurement (see
section "Example (Page 113)": Program "BI_SSFK_MESS_AX1_X.MPF").
Because the various measuring devices offer different support options for the practical implementation in conjunction with a
SINUMERIK control, this process is only generally described in the following referred to a control.
Note
The measurement for determining the leadscrew error should only be carried out during the first commissioning if, in the
machine data, the traversing directions of the axes in relation to the machine coordinate system have been correctly set.
Carrying out commissioning
1. Specify the number of compensation interpolation points
Each axis should be assigned to one compensation table each for the positive and negative traversing directions. The
number of compensation interpolation points is defined using the following machine data:
MD18342 $MN_MM_CEC_MAX_POINTS[<t>] (maximum number of interpolation points for sag compensation)
with: <t> = Index of compensation table
Permissible range: 0 ≤ t < 7
CAUTION
User data loss
ALARM 4400 is output when changing MD18342:
"Reorganization of the buffered memory!"
In order that an automatic memory configuration is possible but keeping all of the data that has been entered up until
now, no system boot (POWER ON) must be executed without first performing a series machine startup.
Function Manual
01/2017
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