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We recommend that you leave JP3 set to the default DI0 and DI2
(both jumpers in the left-hand position), because this setting is
required by the software driver. This setting has the same effect as that
achieved by SW6 positions 7 and 8 on the PCL-718 card.
Jumper JP4 selects reference voltage source for the PCL-818L's D/A
converters. You can use the card's internal reference or supply an
external reference.
Set JP4 as shown below:
External ref.
INT
When you set JP4 to INT, the D/A converter takes its reference
voltage input from the card's on-board reference. Jumper JP5 sets the
on-board reference to either -5 V or -10 V. With JP4 set to INT, the
D/A channel has an output range of 0 V to +5 V or 0 V to +10 V.
When you set JP4 to EXT, the D/A converter takes its reference
voltage input from pin 31 of connector CN3. You can apply any
voltage between -10 V and +10 V to this pin to function as the
external reference. The reference input can be either DC or AC
(<100 KHz).
When you use an external reference with voltage V
program the D/A channel to output from 0 V to -V
the D/A converter as a programmable attenuator. The attenuation
factor between reference input and analog output is:
Attenuation factor = G / 4095
where G is a value you write to the D/A registers between 0 and 4095.
For example, if you set G to 2048, then the attenuation factor is 0.5. A
sine wave of 10 V amplitude applied to the reference input will
generate a sine wave of 5 V amplitude on the analog output.
EXT
Internal ref. (default)
INT
EXT
, you can
ref
. You can also use
ref
Chapter 2 Installation
13
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