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3. Analog Input
（
AI
）
This chapter describes measuring the relevant content of analog input signals on PCI-5000 series
data acquisition devices. AI here is short for Analog Input.
Each analog input channel of PCI-5000 series data acquisition device has an independent ADC, so
there is no time difference between the measured data of each channel during analog input
acquisition, and multi-channel synchronous acquisition is realized.
3.1.
Signal connection methods
PCI-5000 series data acquisition devices support analog input acquisition connection methods of
grounding reference single-ended input The positive end of the analog input signal is connected to
the AIn port of the analog input port, and the negative end of the input signal is linked to the GND
port.
3.2.
Signal acquisition mode
When the PCI-5000 series data acquisition device performs analog input measurement, supports
the following three acquisition modes:
Continuous acquisition mode
Limited collection mode
Single read
The sampling rate of the first two modes adopts hardware timing.
The limited number acquisition mode is called OneShot mode.
Continuous acquisition mode
Continuous acquisition mode refers to continuous and uninterrupted collection of data at defined
sampling speed.
In continuous acquisition mode, after the AI acquisition is triggered, the acquisition device collects
the signal at a fixed sampling speed, buffers data into FIFO, and continuously uploads the data in the
FIFO to the computer memory buffer. The user program only needs to continuously process the data
in memory to achieve continuous uninterrupted data acquisition.
If the user program does not process the data fast enough, the data will gradually fill the 2M points
of storage space in computer memory buffer. New data cannot be written correctly after the memory
is filled up, resulting in discontinuous data.
Limited number acquisition mode
Limited number acquisition mode (OneShot mode) refers to one time acquisition to get the set
number of collection points at the set sampling speed.
