Field Service Manual December 2003
Page 125 of 276
• Output Signals : Two square wave signals S1 and S2 which are 90 degrees
phaseshifted, and a reference impuls (RI) are obtained. The reference impuls has
an electrical width of 90 degrees. The output is obtained via line driver, and so the
inverted signals are also available. The signals are also 10 times refined so that the
electrical grating pitch is now 1.016 micron.
- the fase shift is 90 degrees +/- 10 degrees
- reference pulse width is 90 degrees +/- 10 degrees
- grating pitch mechanical 10. 16 micron
- grating pitch electrical 1.016 micron
- position reference pulse : centred around 135 degrees refered to signal S1 (and
if signal S1 is leading 90 degrees against signal S2)
- The direction of movement can be detected from the phaseshift between S1
and S2.
- All signals are available in the 'LINE DRIVER RS422c STANDARD'. This
means that the inverted signals are also available and that the Treshold
Voltages are greater than 0.2 V or smaller than -0.2 V. Any difference
between the differential signals ( S1 - inverted S1 ; S2 - inverted S2 ; RI -
inverted RI ) greater than 0.2 V or smaller than -0. 2 V can then be detected by
IC 10 on the L2MRSF-Board.(For Maccon refering to Maccon layout &
Maccon info(description of the boards)). This means also that everything is
covered by the mechanical mounting of the measuring scale. One can not
adjust a measuring scale in an electrical manner: or the signals are good and
the measuring scale is good, or the signals are bad and you have a broken
rneasuring scale (if the scale is mounted mechanicaly in the proper way !!!)
One can verify all these signals on IC1O on the L2MRSF-Board, which is a
Line Receiver 26LS32. (For Maccon refering to Maccon layout)
(see next page for more information about the signals)
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