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The 16.154 Minus VDFG Unit is identical to the 16.156 Plus VDFG, except that diode
and reference polarities are reversed.
Similarly, the 16.306 and 16.304 Units are
identical except for diode and reference polarities.
Therefore, the 16.156 Plus
(fixed breakpoint) VDFG and the 16.304 Plus (variable breakpoint) VDFG are the only
units described in this section.
b.
Setup Procedure (Fixed Breakpoint VDFG's)
A simplified diagram and a typical patching scheme for the 16.156 Plus VDFG is
shown in Figure 17.
This information is applicable to the other VDFG's, however,
the input voltage polarity restrictions for each unit must be observed.
The function shown in Figure l8a is used to illustrate the procedure for setting up
a fixed breakpoint VDFG.
Proceed as follows:
(I)
Prepare a table (Figure l8b) of the appropriately scaled voltages de-
sired at the output of the VDFG when the input voltage is equal to 0, +1, +2, +3,
+4, +5, +6, +7,
+8,
+9, and +10 volts.
(2) Open the door below the control panel and slide the appropriate VDFG
tray forward, exposing the adjustment potentiometers.
Patch the circuit shown in
Figure l8c.
(3)
Turn the VDFG potentiometers fully counter-clockwise.
Temporarily
disconnect the output of amplifier 1 from the VDFG, and ground the +IN terminal.
Adjust the PARALLAX pot to obtain the appropriate output voltage, in this case
+2.6 volts.
(4)
Re-connect amplifier 1 to the +IN terminal, and adjust the setup
pot to provide an input of +1 volt.
Adjust the +1 volt pot until the correct
output voltage is reached (+3.3 volts in this case).
(5)
Apply an input of +2 volts.
Adjust the +2 volt pot until the correct
output voltage is attained.
For the sample function shown, this value is +4.0 volts.
(6)
Continue to change the input voltages sequentially, and obtain the
correct output voltage for each input increment by adjusting the appropriate slope
potentiometers.
The slope adjustments must be made in order, going from 0 to +10
volts (O to -10 volts for a Minus VDFG).
(7)
Check the complete setup (preferably with a plotter) to ensure that the
function
i~
well adjusted.
Slide the VDFG tray into its operating position and
close the cover.
£.
Setup Procedure (Variable Breakpoint VDFG's)
The variable breakpoint VDFG's provide for ten variable breakpoints in the interval
from 0 to +10 volts (Model 16.304), or 0 to -10 volts (Model 16.306).
This feature
adds considerably improved flexibility and accuracy over the fixed breakpoint VDFG's,
but requires a more complicated setup procedure.
This sub-paragraph provides general
setup information, and includes a procedure for the setup of a sample function.
The
sample function selected is complex, and is intended to illustrate the step-by-step
procedure for setting a function.
It is suggested that the operator set up this
function to become familiar with the characteristics of the VDFG and the setup
steps required.
34
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