Introduction

An Active X control can best be described as a software module that performs a specific function. Active X Controls eliminate pages of programming and greatly reduce mistakes. In one line, you’ll be able to refer to numerous lines of code that have already been tested and are ready to go to work for you. Though these controls may be used with multiple programming languages they are best used with VisualBasic.

Supported Hardware: DI-145, DI-149, DI-155, DI-148U, DI-150, DI-151, DI-154RS, DI-158 Series, DI-190, DI-194RS, DI-195B, DI-4xx products, DI-5xx products, DI-7xx products, DI-1100, DI-1110, DI-1120, DI-2008, DI-2108, DI-2108P, DI-4108, DI-4208, DI-4718B, DI-4730, DI-5001.

Active X controls have three types of functions: properties, methods and events. Properties are the attributes of the control. They describe the appearance and operation of the control. Methods are function calls inside the control that allow information about the control to be sent or received. Events are notifications generated by a control in response to a particular occurrence.

The following is a brief description of each control.

DataqSdk

DataqSdk provides access to the most basic elements of data acquisition hardware. In contrast, the WinDaq control relieves you of general data acquisition housekeeping and delivers scaled waveform data to your application. The DataqSDK control is for use with all supported hardware (listed above) and programs may be easily transformed to acquire data from low-end starter kits (like the DI-194RS) to a high-end data acquisition system (like a DI-730).

Features include:

•  Data acquisition mode definitions for continuous and triggered data acquisition.
• Sample rate, channel, single-ended, and differential definitions and various other scan list items.
• Immediate mode access to digital I/O and analog outputs.
• Access to acquired data using either burst or streaming methods.

Limitations include:

• DataqSdk currently does not offer streaming DAC output.

DQChart

DQChart is provided to allow basic charting capability - a visual representation of your data. For use with all supported hardware.

Features include:

• Access to acquired data using either burst or streaming methods.
• Plots up to 16 channels on the same chart.
• Allows analog or digital plotting.
• Displays color legends for each waveform in the upper left-hand corner of the chart.
• Supports scaling and offsetting via mouse control.
• Supports WinDaq compatible event marking.
• Plots a specified channel from a data stream. 

DataqFile

DataqFile has two components: WriteDataqFile and ReadDataqFile. For use with all supported hardware.

WriteDataqFile can be used to create a WinDaq-compatible file. Although your data acquisition program may not use WinDaq software, it may still be beneficial to allow the data files your program creates to be accessed, displayed and manipulated using WinDaq Waveform Browser (WWB) software. This control ensures that the files created by your program may be used with WWB and ReadDataqFile.

Features include:

• File manipulation utilities that allow controlled access to data.
• +/- Full-scale definitions per channel in engineering units.
• Sample rate throughput definition that is used by WWB for all timing measurements.

Limitations include:

• Supports only regular WinDaq Files (i.e., does not support different channels sampled at different rates).
• Does not support commented event markers.
• Does not support user annotation.

ReadDataqFile can be used to read WinDaq-compatible files. This control provides a convenient way to perform special operations (custom analysis or exporting requirements) on a WinDaq file.

Features include:

• Open and close file manipulation capability.
• File navigation utilities.

Limitations include:

• Supports only regular WinDaq files - i.e., no support for different channels sampled at different rates (using WinDaq/Pro+) or files saved to SD/MMC memory using a data logger (.wdc files). Note: Both types of files can be converted to "regular" .wdq files using File > Save As... > option 2) Binary (with CODAS header) in WinDaq Waveform Browser software.
• Does not support commented event markers.
• Does not support user annotation.

WinDaq

The WinDaq control can be used to eavesdrop on a data stream being acquired by WinDaq Data Acquisition software (WinDaqLite/Pro/Pro+). Using this control you can return a single value or the latest frame of data (data frame methods) or you can monitor the whole data stream (data stream methods).

The primary advantage of this control is to relieve you of the tasks associated with initializing data acquisition. These include, but are not limited to, scan list initialization and management, sample rate definitions, engineering unit scaling, and many others. These tasks are performed by WinDaq turnkey data acquisition software at a very high level. The data acquired by the application can be made available in real time by this control. In this manner, the control allows you to concentrate on specific requirements of the task at hand without regard to mundane and obscure data acquisition details. For use with all supported hardware.

Features include:

• Derives the number of channels, sample rate, engineering units scaling, slope and intercept scaling constants, and full-scale ranges in engineering units as defined by WinDaq software for each channel.
• Provides access to acquired channel data using one of three options: immediate mode by defined channel; immediate mode by all enabled channels; and a stream approach that guarantees waveform continuity.
• Allows asynchronous access to the hardware's digital input and output ports and analog output ports.

Cautionary note: During program development, while your program is still in the interpretive mode, be sure that the WinDaq application is not terminated before the program that is accessing the application. Terminating WinDaq before your application will cause your host program to become unstable. This anomaly is not an issue after your program is compiled into an executable file.

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