A/D Conversion Procedure; A/D Signal Source Control - NuDAQ PCI- 9113A User Manual

5.1.1

A/D Conversion Procedure

For using the A/D converter, users must know about the property of the
signal to be measured at first. The users can decide which channels to
be used and connect the signals to the PCI-9113A. Refer to the chapter
3 'Signal Connection'. In addition, users should define and control the
A/D signal sources, including the A/D channel, A/D gain, and A/D signal
types. Please refer to section 5.1.2. For A/D signal source control.
After deciding the A/D signal source, the user must decide how to trigger
the A/D conversion and define/control the trigger source. The A/D
converter will start to convert the signal to a digital value when a trigger
signal is rising. Refer to the section 5.1.3 for the two trigger sources.
The A/D data should be transferred into PC's memory for further using or
processing. The data can be read by I/O instruction, which is handled
directly by software or transferred to memory via interrupt. Please refer to
section 5.1.4 to obtain ideas about the multi -configurations for A/D data
transfer.
To process A/D data, programmer should know about the A/D data
format. Refer to section 5.1.5 for details.
5.1.2

A/D Signal Source Control

To control the A/D signal source, the signal type, signal channel and
signal range should be considered.
Signal Type & Signal Conditioning
The A/D signal sources of PCI-9113A could be single ended (SE) only.
Three are 32 SE A/D channels on board. The R/C filters (attenuantors)
are on board for every channel. The RC circuits for each channel is
shown in the following diagram, where 'n' is the channel number. User
can install the R, C for special purpose such as attenuating the voltage to
increase the input voltage range.
24 Operation Theorem