Table of Contents
Advertisement
Rotate the breakpoint pot 1 counter-clockwise while observing
the meter.
At first, nothing will happen, but when the break-
point is in the vicinity of Xl the output will start to change.
Rotate the pot until the output changes by 0.1 volt.
The
first breakpoint is now correctly set at Xl.
Do not change
any slope pot settings at this time.
(j)
Repeat Step
(D,
setting the value of potentiometer_ 1 to the
value required for the second breakpoint (Figure 19b) , or move
the long patch cord to pot 2.
Place the function switch in the
center position and repeat Step
(g)
above.
Repeat Step
<10,
adjusting the breakpoint 2 potentiometer for a
0.10 volt change on the meter.
For instance, potentiometer 14
is adjusted until the meter reads a null (zero volt) in Step
(10.
The breakpoint potentiometer is then rotated until the voltmeter
reads +0.10 or -0.10 volt, whichever is appropriate.
Set the
remaining breakpoints in this manner.
(j)
The breakpoints are now set correctly, but the slopes are still
set at the extremes (approximately' ±l volt per volt).
It isa
good idea to plot the output of the DFG versus the input at
this tTIme.
The resulting curve (Figure 20b) will not look like
the desired curve, but it enables one to check at a glance that
the breakpoints are properly located.
To make this plot, adjust the DFG input voltage to XII (the
endpoint of the interval of interest - usually +10 volts) and
adjust the
CENTRAL
SLOPE pot so that the output is approximately
zero.
This does not affect the breakpoint location, but merely
shifts the entire curve so as to provide a more easily read
plot.
Patch the configuration shown in Figure 21,
and
place the com-
puter in the operate mode.
An
initial condition voltage of -1
volt is provided so that the plotter pen describes the entire
curve under consideration.
With an input of
-1
volt to the
integrator, the plotter will cover the range of -1 to +10 volts
in 11 seconds.
(5)
Setting the Function Values.
Set all slope pots approximately to zero.
This adjustment is not critical, and could be omitted, but it helps prevent ampli-
fier overload during setup.
Since fully clockwise rotation of the slope pot pro-
duces a slope of +1 volt per volt and fully counter-clockwise rotation produces
-1
volt per volt, zero slope is found with the pot at the center of its rotation.
Since the pots rotate through approximately 300 degrees, zero slope may be approx-
imately obtained by watching the screwdriver blade and rotating the pot a little
less than 180
0
from its extreme position.
43
Advertisement
Table of Contents
