
Computer interfacing
they all take natural quantities as their input and pro-
duce an analogue output. However, there is one type of
transducer that is capable of producing a digital output
directly — the digital shaft encoder.
The digital shaft encoder
This is the only true transducer capable of giving a par-
allel digital output. It comprises a circular disc on which
a series of radial patterns of light and dark areas, each
representing a binary number, is applied, to be read by
a number of sensing heads. Each of these binary num-
bers corresponds to a unique angular position of the disc.
Thus,
since an
8-bit
number can take any of 256 differen ...