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68
SPECIAL DEVICES
brush is wired, the card will sort into the 12 pocket.
2. If all the multiple column brushes read blank
columns in the card, the card will sort into the 12
pocket. If, however, one or more brushes sense selected
information, and one or more brushes sense blank
columns, the blank columns will not be analyzed as
unselected information and the card will pass into the
reject pocket.
3. If only selected holes are sensed by the multiple
column brushes, the card will pass
to
the reject pocket.
4. If one or more brush hubs are plugged to the
sorting common, the impulse from the brush hubs will
be applied directly to the starter anode through the
regular sorting commutator. In order to sort to the
value sensed by the brush, both the zero-eliminate and
multiple column selection switches must be off.
5. If a brush selection switch is set to
SORT,
and
that brush senses a hole in the card, the impulse will be
applied directly
to
the OA4G starter anode. This im-
pulse will pass through those switches directly below
the switch set to
SORT
and through the regular sorting
commutator. In order to sort to the value sensed by the
brush, both the zero-eliminate and multiple column
selection switches must be off.
ZERO ELIMINATION
Static Circuit Conditions
A 2D21 thyratron tube (zero-eliminate control) is
connected across the
DC
machine circuit with a 2000
ohm resistor and the R-ZE relay in series with its anode.
Negative grid bias for this tube is obtained in the same
manner as for the MCS control tube. The control grid
of the zero-eliminate tube is connected to the number
13 common brush on the MCS selecting commutator
through two 500K resistors.
Operation of the Zero-Eliminate Control Tube
When any brush in the multiple column brush unit,
with the exception of the units column brush, senses
significant digit punching (1 through 9) in the card,
a positive pulse is available at the lower punching hub
for that position. When wired for zero-elimination, this
impulse is directed into the zero selector hub and to the
common of the selecting commutator. The zero brush
contacts the A segment at zero time only. From the
common of the selecting commutator, the pulse is ap-
plied to the grid of the zero eliminate 2D21 tube
through common brush 13 and the two 500K resistors.
This pulse cancels the negative bias on the grid of the
2D21, causing it to fire and pick up the R-ZE relay.
The tube remains in conduction and the relay remains
energized until the end of the card cycle when com-
mutator 2 breaks. The
N/O
R-ZE relay points shunt
commutator 1 to allow this condition.
At
6 3 4"
after 12 time, commutator 3 makes and ap-
plies the plus
DC
machine voltage to the starting anode
of the OA4G through the following circuit: from the
positive
DC
terminal 13, through the CCR-B point, con-
tact roll cover switch 1, card lever contacts, commutator
2, pin 3 on octal plug B, the R-ZE point, the 2000 ohm
resistor, to pin 6 on the MCS control tube, through the
47K resistor, pin 6 on octal plug B, commutator 3,
zero-eliminate switch 1-R
ON,
multiple column selec-
tion switch 1-R
OFF,
to the outer brush of the regular
sorting commutator, through pin 5 on octal plug A,
the 47K resistor, to the starting anode of the OA4G.
Application of this voltage fires the OA4G and causes
sorting of the card into the 12 pocket.
Zero-eliminate switch 2-L prevents the MCS con-
trol tube from firing even though some brushes may
have sensed a 0 punch in the card.
If none of the brushes to the left of the units posi-
tion sense a significant digit in the card, the zero elimi-
nate control tube is not fired and R-ZE is not picked
up. When commutator 1 breaks at
3 3 2
before 0, the
voltage is removed from the contact roll and the anode
circuits of both 2D21 tubes. This prevents any brush
from reading a 0, 11 or 12 hole in the card. It also
prevents the OA4G tube from firing when commuta-
tor 3 makes. If, under the above conditions, the units
position brush senses a blank column or a 0, lIar 12,
punch, the card will pass to the reject pocket.
If the units position brush senses a 1 through 9
punch in the card, this impulse is applied directly to
the starting anode of the OA4G. The ClCcuit is through
the brush selection switches to the left of the units posi-
tion and the regular sorting selector commutator. Ap-
plication of this impulse to the starting anode of the
OA4G causes it to fire and sort the card into the pocket
corresponding to the value of the punching sensed.
Significant digit values, which are sensed by the units
position brush as described above, are sorted to their
corresponding pocket regardless of whether or not the
zero eliminate tube has been fired.
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