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Model S62A
Section IV
print wheel at that position.
The number is then printed.
When the data source
initiates another print command, the scan signal occurs a short time later and
causes amplifiers 0109,0110, and 0111 to energize the pawl magnet if the
data input has changed.
The print wheel rotates.
The magnet remains energized
until diode CRI0S has +lS volts applied from the matrix.
4-4. ANALOG CIRCUITRY OPERATION.
Sinc e the column board s contain stored binary information, an analog function
can be derived to drive a strip chart recorder.
The analog circuitry provides
the following:
a. A graphic presentation whereby the trend of recorded data can be seen at
a glance.
b. Three digits of analog information where full scale on the recorder may
be a few parts per million of the original printed reading.
c. A recording where an increasing numerical count is always an upward
direction on the strip chart recording.
d. An analog recording which is always on scale.
To derive the analog voltage a switching arrrangement is used which utilIzes
the stored binary data from three consecutive columns of the printed data.
Any three of the first nine columns may be used as well as the first two right
hand digits.
The binary output data is weighted according to the code required by the
storage units.
Four resistors are used to develop a staircase function from
the four storage binaries.
The four weighting resistors are in the ratio 4221.
Refer to the analog circuitry schematic.
Each of the three storage decades
then produces a staircase function with a level proportional to the numerical
value of its stored binary data.
The three staircase voltages are then mixed in proportion to their decade
value or in the ratio of 1, 10, 100, to produce a single staircase function
1000 part in amplitude.
Each discrete step then represents. 10/0 of full scale
and for practical purposes is an analog function.
This output voltage is then
attenuated and applied directly to a potentiometer type strip chart recorder.
The analog signal is also applied to an amplifier whose output can be used to
drive a 1 rna
type galvanometer recorder.
Diode clamps insure accurate voltage levels before mIXIng.
Compensation
elements maintain constant output over wide temperature extremes.
01081 -1
4-3/4-4
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