Renishaw RCU10, Installation And User Manual, Page: 35 / 202

2-12 System design
2.5 Referencing
2.5.1 Signal format and re-synchronisation
When using a laser encoder, the exact phasing of the reference signal relative to the sine
and cosine signals cannot normally be guaranteed, because the position of the interfering
light waves is not mechanically registered relative to the position of the reference switch.
To overcome this, the RCU10 includes a circuit that re-phases the position signals so that
the reference mark output occurs synchronised and in a repeatable position.
Digital interface re-synchronisation
The output is produced when A is high and B is high. The re-synchronisation process
ensures a reference output will occur at 5 ±1 output quadrature counts later than the
reference input.
Figure 2.7 – Digital interface re-synchronisation
A quad
Bquad
Reference Input
Reference Output
5 Output Counts
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