The Data Acquisition Engine (Data Acquisition Toolbox)

Data Acquisition Toolbox

The Data Acquisition Engine

The data acquisition engine (or just engine) is a MEX-file DLL that:

Stores the device objects and associated property values that control your data acquisition application (see page 2-8)
Controls the synchronization of events (see page 2-19)
Controls the storage of acquired data to disk or memory (see page 2-22)

While the engine performs these tasks, MATLAB can be used for other purposes such as analyzing the acquired data. That is, the engine and MATLAB are asynchronous.

One of the main features of the Data Acquisition Toolbox is the data analysis power provided by the MATLAB environment. Therefore, it is important to understand how acquired data becomes available to the MATLAB workspace and what is meant by "acquiring data."

Data Flow

In a practical sense, acquiring data means that data is flowing from your hardware device into the data acquisition engine, where it is temporarily stored in memory. The data is stored temporarily because it can be overwritten. The rate at which the data is overwritten depends on several factors including the allocated memory, the acquisition rate, and the number of hardware channels from which you acquire data. However, the stored data is not automatically available in the MATLAB workspace. You must explicitly extract it from the engine in a timely way so that no data is lost.

To summarize, the flow of acquired data consists of two independent steps:

1.: Data flows from the hardware to the engine

2.: Data flows from the engine to MATLAB and/or to a disk file

These two steps are illustrated below.

Extracting data from the engine is described in "Managing Acquired Data".

Saving data to a disk file and loading data from a disk file are described in "Logging Information to Disk".

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