Modulo
Function description 57
Version: 1.5
11.4.1 Prime number gears
Prime number gears always have an odd number of teeth and are often used in practice to minimize wear of
the individual teeth. If one gearwheel of a pair has a prime number as the number of teeth, the number of
meshings of the same pair of teeth is minimized. This gear type is parameterized with IDN P-0-0279 “Modulo
Value Remainder”.
Application example
Turntable with a gear reduction ratio of 63/17.
On the motor side, 360 ° (1 revolution) correspond to 2
20
increments.
The resulting modulo period at the gear output (turntable) is:
2
20
inc x 63/17 = 3885899.2941176470588235294117647 inc
= 3885899 + 5/17 inc
or = 3885900 – 12/17 inc
The modulo period of the AX5000 (S-0-0103) can only be parameterized with an integer value. Thus, if
3885899 inc is used as modulo period, the resulting error is 5/17 inc per modulo period on the turntable side
and 5/17 x 63/17 = 1.08997 inc on the motor side. Because this error accumulates with each modulo
revolution, the error becomes significant after n modulo revolutions in the same direction.
Extended parameterization
To avoid the accumulating error illustrated in the above application example, IDN P-0-0279 “Modulo Value
Remainder” was implemented in the AX5000.
This IDN can be used to enter the residual (error) of the modulo period parameterized in S-0-0103, relative
to the actual modulo period. The parameterized value may be positive or negative. It is best to always use
the smallest absolute value. In the above example, this would be 5/17 with S-0-0103 = 3885899. The same
result is obtained with the value
-12/17 with S-0-0103 = 3885900. However, this option results in a greater position jump at the correction
point, since |-12/17| > |5/17|.
The drive corrects the modulo calculation as if the actual modulo period were to correspond to the value
parameterized in
S-0-0103. Consequently, when calculating the NC scaling, the value in S-0-0103 must be used. The
resulting scaling factor is
360°/ S-0-0103 = 360°/3885899 inc.
To Next Page
Loading...
Need help?
General
