CN0170 HARDWARE MANUAL
INPUTS, ANALOG:
The CN0170 has four analog inputs. Two analog inputs are dedicated for
use with the Joystick instructions while the remaining two are designated
as general-purpose inputs.
The analog inputs are multiplexed into a sample and hold circuit. The
output of the sample and hold circuit is converted by an 8-bit digital to
analog converter and read into the CN0170 memory. The user may read
this data over the RS-232A interface. The analog inputs are converted in
sequence, with an A/D conversion occurring every 3.9 milliseconds. This
means any particular analog input is sampled 32 times a second.
The analog input voltage range must be between zero and 5 VDC. Care
must be taken not to exceed these limits or damage may result. The inputs
appear as a 200 ohm resistor in series with a 0.01
μ
f capacitor.
The user may select one of two analog conversion ranges. The A/D can
have a zero to full range of 0-5 volts or a reduced range of 2-3 volts. The
reduced range makes the analog inputs directly compatible with
potentiometric joysticks.
Figure 15, Range Option Header
The Range Option Header is
used to select the appropriate
A/D conversion range. The
CN0170's cover must be
removed for access to the
header. Remove the four screws
on the bottom of the CN0170
and lift the cover up at the LED
indicator end.
See Figure 15 for the location of
the Range Option Header. For
0-5 VDC conversion range,
connect the pins together with
the jumper block provided.
For 2-3 VDC conversion range, remove the jumper block from the pins. The
selected conversion range will apply to all four analog inputs.
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Summary of Contents for CN0170
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