HEIDENHAIN PWM 20 - Manual (Page 208)

November 2014 Interface description 209
7 Interface description
7.1 General information
The specifications in the brochure "Interfaces of HEIDENHAIN encoders" ID 1078628-xx
apply.
Supplementary information, e.g. on older interfaces and encoders, is part of the description
below.
7.2 Analog interfaces
7.2.1 Incremental signals 11 µApp
The sinusoidal incremental signals I
1
and I
2
are phase-shifted by 90° elec. and have a signal level
of 11 µApp typ. The usable component of the reference mark signals I
0
is approx. 5.5 µA. The
signal amplitudes refer to U
P
= 5 V
 5 % at the encoder. The signal amplitude changes with
increasing scanning frequency (see Cutoff frequency).
The linear encoders with single reference marks have a reference mark every 50 mm of the
glass scale, one or several of which can be activated by means of a selector magnet (on old
encoders: optically using a selector plate). The quiescent level of the output signal is increased
by approximately 22 µA; the usable component G of the reference mark signal to be evaluated
is based on this level. Signal peaks with amplitude G also appear in the quiescent level for the
inactive reference marks every 50 mm.
Incremental signals Two sinusoidal current signals I
1
and I
2
Note
Also see "Interfaces of HEIDENHAIN encoders" brochure, ID 1078628-xx.
Note
The stated tolerances are standard values!
The tolerances of measuring systems for high resolutions (e.g. angle encoders) and large
temperature ranges (e.g. motor encoders) are tighter!
The supply voltage of 5 V
5% at the encoder has to be ensured!
Signal level M * 7 to 16 µApp
(typ. 11 µApp)
Asymmetry /2M 0.065 TV
15°
Signal ratio M (I
1
) / M (I
2
0.8 to 1.25
Phase angle /2 90°
10° el.
* Old LS series
LS 50x; LS 80x (e. g. LS 503, LS 803)
Ie1, Ie2: 15 ... 35 µApp
P - N = ˆ
1 2
+