VICI Selectors (multiposition) Standard electric - Manual (Page 11)

 Actuator Modifications
Description of the Encoder Discs
The encoder disc provides a means
of signalling the position of the
actuator and relaying that informa-
tion to the logic circuit. If the disc
is thought of as consisting of five
concentric bands, (like an archery
target) the outside band contains
the “strobe bits.” (See
Figure 7)
These slots signal the logic circuit to
read the position information and to
stop the motor when the information
conforms to the input command.
The next bands, in order toward the
center, denote units of one, two,
four, and eight.
In the 4-position disc illustrated in Figure 7, the location that corresponds
to the strobe bit for Position 1 contains only a slot in the “ones” band, so it
registers as “one”. Moving counterclockwise to the next strobe bit, the slot
is in the “twos” band and is read as “two” for Position 2. Since there is no
“threes” band, the information for Position 3 requires a slot which fills the
“ones” band and the “twos” band, registering as 2 + 1, or 3. Position 4 has
simply the one slot in the “fours” band. The 4-position disc affords the clearest
illustration of the principles involved, which are the same all the way up to
the 16-position. To continue the examples, Position 5 has slots in “fours” and
“ones”, Position 9 has slots in “eights” and “ones”, and Position 15 uses the
whole range, 8 + 4 + 2 + 1. The last position location on a 16-position disc
utilizes the last option – no slots at all.
The 4 x 2, 6 x 2, and 10 x 2 are slightly different. The 4 x 2 is essentially an
8-position actuator, but instead of reading out Position 1 through Position 8
it goes from Position 1 to Position 4 and then repeats the succession. Like-
wise, the 6 x 2 does two sequences of Positions 1 through 6 and the
10 x 2 does two sequences of Positions 1 through 10.
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