Table of Contents
Advertisement
8.4.3.11
Plotting.
Once the function is set, a continuous plot
of output versus input should be made, which serves as part of the problem
documentation.
Such a plot may be made on the 580 without repatching.
The
580 DFG setup panel contains a built-in ramp integrator to provide a smooth
sweep for the input.
Slide out the upper DFG drawer, and make the appro-
priate plotter connections at the terminals on the right.
Turn on the OFF/
ON switch ON, and set the IC and RATE switches appropriately.
To sweep
from -Reference upwards, turn the RATE switch to tf+".
To sweep from +Refer-
ence downwards, put. the RATE switch to
Il_";
this reverses both the rate and
the IC.
To start the sweep at x
=
0, turn the IC switch OFF.
To make. a plot, put the switch marked RESET/OPERATE to the OPERATE posi-
tion.
The rate of the sweep is determined by the RATE pot; a little experi-
menting will produce a setting that does not overdrive the plotter.
When
the plot is completed, put the RESET/OPERATE switch to the RESET position
and turn the OFF/ON switch OFF.
8.4.4
Insufficient Slope
During the above procedure, it may happen that a particular function value
cannot be obtained.
If the slope pot is rotated to the end of its travel
(ten times) and the function value still has not been reached, the first
thing to do is to check Table 8.2 and make sure you are setting the right
pot.
Also, make sure the slope polarity switch is in the right position.
Assuming that no such error has been made, the problem is probably one of
insufficient slope.
For each segment there is an upper limit to the amount of slope change that
it can introduce; this is the amount produced with the slope pot fully
clockwise.
On the 580, a maximum slope change of 1.0 may be obtained with
one segment, assuming the slope multiplication switch is in the "1" posi-
tion (see Paragraph 8.4.3.5).
Other positions of this switch allow for
slope changes as great as 32.
The slope multiplication switch works by changing the effective feedback
resistance on the output amplifier, thus providing greater gain.
For every
steep or sharply curving functions, a position other than "1" may be nec-
essary.
There is also a limitation on the initial slape fICO).
This limi-
tation is
~.O
if the MULT switch is in the "1" position, and it goes up in
proportion to the setting on this switch, so that the maximum value is 96
(3 x 32).
The effective resolution of the slope pots decreases with higher gain; at
high settings a small motion of the pot produces a large change in the
output, making accurate setup difficult.
Also, electrical characteristics
such as bandwidth are degraded at high gain setting.
For this reason, it
is not desirable to use any more gain than necessary in generating a parti-
cular function.
A conservative procedure is to set the switch initially at "1", and pro-
ceed to set the function until insufficient slope is encountered, then
try a setting of 2 and try again.
However, this procedure may lead to a
number of false starts, and some methods of estimating the maximum slope
requirement prior to setup is desirable.
8-13
Advertisement
Table of Contents
