A/D Conversion. HP (Hewlett-Packard) NuDAQ PCI-9111HR, PCI-9111DG/HR

4

Operation Theorem

The operation theorem of the functions on PCI-9111 card is described in this chapter. The functions include the A/D conversion, D/A conversion,

Digital I/O and counter / timer. The operation theorem can help you to understand how to manipulate or to program the PCI-9111.

4.1 A/D Conversion

Before programming the PCI-9111 to perform the A/D conversion, you should understand the following issues:

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A/D conversion procedure

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A/D signal source control

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A/D trigger source control

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A/D data transfer mode

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A/D Pre-trigger function

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Interrupt System (refer to section 4.2)

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A/D data format

Note: Because some of the A/D data transfer modes will use the system interrupt resource. The users have to understand the interrupt system (section 4.2) at the same time.

22 • Operation Theorem