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TR-Electronic GmbH 2004, All Rights Reserved
10/01/2014
TR - ECE - BA - DGB - 00036 - 10
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8.11.8.2 Revolutions numerator / Revolutions denominator
Together, these two parameters define the
Number of revolutions
before the
measuring system restarts at zero.
As decimal numbers are not always finite (as is e.g. 3.4), but they may have an infinite
number of digits after the decimal point (e.g. 3.43535355358774...) the number of
revolutions is entered as a fraction.
Numerator lower limit
1
Numerator upper limit CEx-58
256 000
Numerator upper limit COx-58
262 144
Default numerator
4096
Denominator lower limit
1
Denominator upper limit CEx-58
16 384
Denominator upper limit COx-58
65 535
Default denominator
1
Formula for gearbox calculation:
Total measuring range = Steps per revolution *
Number of Revolutions numerator
Number of Revolutions denominator
If it is not possible to enter parameter data in the permitted ranges of numerator and
denominator, the attempt must be made to reduce these accordingly. If this is not
possible, it may only be possible to represent the decimal number affected
approximately. The resulting minor inaccuracy accumulates for real round axis
applications (infinite applications with motion in one direction).
A solution is e.g. to perform adjustment after each revolution or to adapt the
mechanics or gearbox accordingly.
The parameter
"Steps per revolution"
may also be decimal number, however the
"Total measuring range"
may not. The result of the above formula must be rounded
up or down. The resulting error is distributed over the total number of revolutions
programmed and is therefore negligible.
Preferably for linear axes (forward and backward motions):
The parameter
"Revolutions denominator"
can be programmed as a fixed value of
"1". The parameter
"Revolutions numerator"
is programmed slightly higher than the
required number of revolutions. This ensures that the measuring system does not
generate a jump in the actual value (zero transition) if the distance travelled is
exceeded. To simplify matters the complete revolution range of the measuring system
can also be programmed.
