
6.INTERPOLATION FUNCTION B-63323EN-1/03
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M : Number of gear teeth on the position coder [teeth]
N : Number of gear teeth on the spindle [teeth]
L : Thread pitch [machine/rev]
P : Number of pulses received by the position coder [pulses]
∆Z:Tool travel distance
Then, ∆Z is represented as follows:
M
P
4096
L
Z ××=∆
. . . . . . Expression
Error in threading
A threading error is explained below.
Under the following conditions:
- The spindle rotates at a constant speed with no rotation error.
- There is no error caused by the servo system and
acceleration/deceleration.
- There is no machine system error.
the following maximum error per pitch occurs:
N
M
4096
L
×
[mm/rev] L:Thread pitch [machine/rev]
(This expression is derived when P in Expression is 1.)
This error can be reduced by smoothing (setting the number of samples
in parameter No. 5611). (This error is reduced by a factor of 1/16 when
parameter No. 5611 = 4.) This error is a maximum error; errors do not
accumulate.
Setting M:N
(1) Using parameters
Parameter No. 5847 and No. 5848 are used.
(2) Using custom macros
The parameters of (1) above can be read from and written to by
using the following custom macro system variables:
#3013 :Parameter No. 5847
#3014 :Parameter No. 5848
With these system variables, a gear ratio can be sent from the PMC
to the CNC through the PMC window.
When changing the gear ratio from the PMC, observe the timing
chart of Fig. 6.4.2(b).