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Attention
The number of set collection points cannot exceed 2MPts.
4. Digital Input
（
DI
）
This chapter introduces the digital input signal acquisition on PCI-5000 series data acquisition
devices. DI is the abbreviation of Digital Input here.
4.1.
Signal acquisition mode
When the PCI-5000 series data acquisition device performs DI acquisition, it 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
The continuous acquisition mode refers to continuous and uninterrupted data acquisition at a set
sampling speed.
In the continuous acquisition mode, after the DI acquisition triggers, the acquisition device collects
the signal at a fixed sampling speed, buffers it in the 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 collection.
If the user program could not process the data fast enough, the data will gradually fill up the 2M
points of storage space in the computer's memory buffer. After filling it up, the new data cannot be
written into memory buffer correctly, resulting in data discontinuity.
Limited number acquisition mode
Limited number of acquisition modes (OneShotmode) refers to one-time acquisition of the set
number of collection points at the set sampling speed.
In OneShot mode, after the DI acquisition triggers, the acquisition device will start acquiring set
number of data at the set sampling speed and stop the acquisition automatically after. The user
program only needs to read the set data amount from the computer memory buffer.
Single point reading
Single point reading refers to reading the status of the current digital input port once.
