Advantech PCI-1718 Series Manual de usuario descargar pdf (Pagina 31)

23 Chapter 3

When you set JP11 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 ref-

erence input can be either DC or AC (<100 kHz).

When you use an external reference with voltage V

ref

you can program

the D/A channel to output from 0 V to -V

ref

, you can also use the D/A

converter as a programmable attenuator. The attenuation factor between

reference input and analog output is:

Attenuation factor = G / 4095

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.

3.2.4 Internal Voltage Reference, -10 V or -5 V (JP10)

If you use an internal reference voltage (set with JP11), the PCI-1718

cards provide a choice between -5 V or -10 V DC internal reference volt-

age sources.

Table 3-1: Summary of jumper JP10 settings

Table 3.4: Summary of Jumper JP10 Settings

Jumper Function description

JP10 5 V (default)

10 V

1 2 ... 26 27 28 29 30 31 32 33 34 35 36 ... 93 94

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Advantech PCI-1718 Series Manual de usuario Pagina 31