Direction-Dependent Leadscrew Error Compensation; Description Of Functions - Siemens SINUMERIK 840D sl Function Manual

Applied to the example, this means, for instance, that compensation value D
calculated by multiplying each of the function values f_i(500) in the f tables by the function
values g_i(300) in the g tables:
D (500/300) = f_1(1000)*g_1(300) + f_2(1000)*g_2(300) + f_3(1000)*g_3(300) +
z
f_4(1000)*g_4(300)
D (500/300) = 0.2*0 + 0.7*1 + 1.2*0 + 1.7*0 = 0.7
z
5.4.4

Direction-dependent leadscrew error compensation

5.4.4.1

Description of functions

If the direction-dependent differences at the compensation points are excessively high, for
an inconsistent backlash or for extremely high demands placed on the precision, then it may
be necessary to apply direction-dependent compensation of the leadscrew error or
measuring system error (for direct position sensing).
"Direction-dependent leadscrew error compensation" ("direction-dependent LEC" or also "bidirectional
LEC")
For the "direction-dependent LEC", two compensation tables can be used for each axis: One
table for the plus traversing direction and one for the minus traversing direction. The error
deviation at the particular compensation point is entered directly into the table (error =
compensation value). The control then automatically compensates with the opposite sign.
This always automatically results in a linear interpolation between adjacent interpolation
points so that no step-like position changes can occur as a result of the compensation.
Preconditions/activation
The "direction-dependent LEC" is implemented in the SINUMERIK control as a special case
of "sag compensation". This is the reason that the preconditions and conditions of "sag
compensation" apply (see "Compensation of sag and angularity errors (Page 364)").
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.
NOTICE
If the "direction-dependent LEC" is used in parallel to the sag compensation and
compensation of the angularity, then the secondary conditions of these functions must be
taken into consideration together, e.g. the assignment of tables <t> to the particular
function.
Extended Functions
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
K3: Compensation
5.4 Interpolatory compensation
(500/300) is
z
381