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Section III
3-10.
REFERENCE VOLTAGE ADJUSTMENT.
Model 562A
The input voltage applied for any column board must not exceed 150 volts.
That
is the refe renee voltage plus the B CD
It
1
It
level should not be greater than 150 volts.
For instance, if the BCD swing is from 100 volts (tiD" level) to 160 volts (til" level)
then attenuation must be introduced to reduce the "0" level to
94
volts and the
"1"
level to 150 volts.
The minus reference voltage can then be adjusted for
94
volts.
The plus reference level must then be adjusted to 150 volts.
Before a reference voltage can be chosen, the "0" and" I" levels of the equip-
ment supplying the BCD signals must be known.
For instance if the recorder
is connected to a binary counter with a -1248 code, each column board will be
driven by a decade in the counter.
Sometimes binaries in the decades have
different" 1" and" 0" levels, thus a proper reference voltage must be chosen.
If the column board is a -1248 code, then the -reference voltage must be chosen
that includes the "1" levels applied to the A, B, C, and D binaries.
A +reference
voltage must be chosen that will include the "0" levels for the A, B, C, and
D binaries.
If high impedance reference levels are used (above 5000 ohms), suitable by-
passing, providing a time constant of 150
~s,
should be used.
If the BCD drive
is derived from an unregulated supply, then it is desirable to obtain the reference
voltage from the same unregulated supply.
3-11. POWER SUPPLY AND INTERNAL REFERENCE VOLTAGES.
The power supply board, A16, supplies the de voltages required by the recorder.
The power supply also has provisions for providing reference voltages of
-9
to
+17 volts.
The operator can select a value of resistors or breakdown diodes
needed to provide the proper reference voltages.
Connectors P301 and P302
(optional) supply the reference voltages to the column boards.
When using an
external reference voltage, connectors P30l and P302 must be disconnected from
the power supply board if resistors are installed.
Unless specified by the
customer, resistors are not installed.
The proper mounting holes are in the
power supply board and the operator can install the resistors or break-
down diodes required to give the desired voltage.
3 -12. PRINTING A MINUS (- ).
The recorder will normally print a blank with no BCD input.
If the operator
wishes to print a -(minus) for a 1224 code, in place of a blank, proceed as follows:
In table 3-1 under the column headed "character to be printed", find -(minus).
Under the "Binary Input" column, the - charac ter must have a "l" input for
the A and D binaries.
If the column board is a +1224 code, then the external
voltage applied to the A binary input must be at least 4 volts more positive
than the negative reference voltage.
Since the D binary has a
11
I"
supplied
3-6
01081-1
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