Evaluation with incremental signals (sinusoidal or rectangular)
If the incremental signals of the encoder are evaluated (e.g. for ec16 = "10: EnDat,
+ 1Vpp" or ec16 = "13: Hiperface"), the number of signal periods covering a whole
number of motor pole pairs is entered in ec50.
Evaluation of digital encoders
If the connected measuring system is evaluated digitally (e.g. at ec16 = " 11: EnDat
digital“ or ec16 = " 14: BiSS Linear“) the value range of the digital position is en-
tered in ec50, which covers a multiple number of motor pole pairs, i.e. by how
much the digital position word from the encoder changes when a multiple number
of motor pole pairs is passed.
6.1.7.3 Example for evaluation of incremental signals
Assuming the linear motor has a distance from one north pole to the next of 70 mm
(length of a motor pole pair) and a signal period is 22.5 mm. This ratio of 70 / 22.5
is converted by way that the numerator and denominator become the smallest pos-
sible integer values, i.e. in this case: 28 / 9.
The reciprocal of this ratio is 9/28. If you multiply the reciprocal by the ratio, you
have the distance where the integer number of motor pole pairs matches to a inte-
ger number of sine periods.
70mm / 22.5mm x 9 / 28 = 630mm / 630mm.
Thus this virtual rotary drive, divided over its 630 mm circumference, has 9 integer
motor pole pairs and 28 integer signal periods.
These 28 signal periods are set in ec50.
Next, the linear rated speed is converted into the rotatory nominal frequency. The
rated frequency is the number of motor pole pairs that are passed per second at
rated speed.
Rated frequency = rated speed / length of a motor pole pair.
For an assumed rated speed of 4.5 m/s, the following results:
Rated frequency = 4.5 m/s / (70 mm / 1000) = 4.5 m/s / 0.07 m = 64.286 Hz.
For convenience only, 65 Hz is chosen.
At last the number of motor pole pairs is set to 9 with the rated speed, i.e.:
Rated speed = rated frequency / motor pole pairs = 65 Hz / 9 * 60 = 433.333 rpm
To get integer values for rated speed and frequency, both values are multiplied by
3, which results a total of:
rated speed dr04 = 433.33 rpm * 3 = 1300 rpm
rated frequency dr06 = 65 Hz * 3 = 195 Hz
6.1.7.4 Example for evaluation of purely digital linear encoders
With digital encoders, instead of the length of one sine period, the resolution of the
digital position (also called measuring step) must be used, i.e. how far the measur-
ing value must be turned that the position increases by 1.
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