APEX DX-DATX vs RWX File Formats

Posted on January 11th, 2019

One of the more unique (and overlooked) features of APEX DX is its ability to import and read a wide variety of data formats such as DATX, UFF, and CSV files with seamless integration. One of the main selling points to our dynamic data acquisition software, APEX DS is its ability to interface with any kind of hardware and export files in various types, giving the user the ability to view flexible and accurate plots and collect accurate data, no matter what hardware system they choose to use. Similarly, APEX DX gives the user access to easy, repeatable, and accurate data analysis regardless of what kind of acquisition software recorded the data (including competitor data types). This blog post will focus on how APEX DX can easily process file type with its drag and drop tools and compare how it reads the industry standard DSPCON format, DATX and how that format compares to our specialized APEX file type, RWX.

DX Signal Processing Software-Available File Formats

Shown: A list of available DX file formats ready to be processed.

The main philosophy of DX is to create a program that makes data analysis as simple as possible, from when you load in your files, to when analysis has been run and reports have been created. This is why we implemented the drag and drop file processing feature into DX. When processing a file, simply drag it and drop it into DX and the program will automatically generate a processing chain for viewing the data, no matter the file type. Below, you can see an image of 2 identical files processed side by side, on the left is a signal from an APEX formatted .rwx file, and on the right is a DSPCON .DATX file format. Both sets of plots were created by using only drag and drop functionality. You can read more about how DX automatically generates a design to view your data here.

DX Signal Processioning Software-Campbell and Envelope Plots, RWX vs DATX

Shown: Campbell and Envelope plots from an identical RWX (left) and DATX (right) file processed and shown side by side.

Although various data formats contain much of the same information, reading them can sometimes pose a challenge, because information is presented differently in each file. DATAX files are no exception to this rule, but our team at APEX has worked to ensure that this data format opens without an issue, no matter the bit rate or version of the file. However, when creating our own data format (.rwx), we wanted to make up for some of the shortcomings that the DATX file format possesses by ensuring that the information included in each file was more comprehensive. Below is a breakdown of the commonalities and differences between our RWX format and the DATX format.

 

 

Commonalities:

  1.  Setup information is defined at the top of the file as a text stream.
  2. The setup is defined in keyword = value pairs
  3. Sampled data is recorded as binary signed integers (typically 16 bit) that equal the analog-to-digital converter (ADC) bits 
  4. Sampled data is recorded in sequential blocks of constant (sample) size = 2n where n is a positive integer (n is defined in the setup)
  5.  If multiple ADC devices are present, each will have its own file inclusive of the setup so it can be read/processed independent of other device files

 

Before discussing the differences between the file formats, it is important to note that there are different “types” of dynamic data. When our APEX DS Dynamic Data Acquisition Software is used as the recording device, the user is permitted to define a channel as one of two types of data; a “parameter” or a “signal”. A “parameter” is a channel that is displayed as a once-per-block value (a block contains n samples – see #4 above). Typically, these are sensors that measure data that change slowly relative to dynamic channels. Typical sensors are: speeds (tach based and voltage proportional), temperatures, flow rates, certain pressure measurements, and vane angles, among others. In contrast, “signals” are (dynamic) channels that are typically transformed into the frequency domain, such as strain gages, kulites, and accelerometers.

 

The most significant difference between the RWX and DATX file formats is the RWX format supports multiple types of processed data in addition to the raw data. The most basic data is the sampled “raw” data defined in #2 above. In addition, “parameter” data as well as other processed data types may also be stored depending on the setup (the setup determines how the data is processed). These different types of data are stored using “packets”. Packets contain a “header” and a “payload”. The header of the packet contains the packet “type” while the payload contains the data. This technology permits processed data to be interlaced with the raw data.

 

 

Other Significant Differences:

  1. The RWX setup contains all the necessary information to process the data, including FFT size, FFT window, filters, formulas, etc., as well as all the digitization and signal conditioning settings. Therefore, upon playback, the data is processed identically as during acquisition.
  2. RWX format supports duplicate or virtual channels
  3. RWX format supports compression to reduce the file size
  4. DATX format is simpler format
  5. RWX format is more complex but is easy to extend for support of other types of raw or processed data. In addition, an API is available for easy and efficient access.

 

So, while file type is an important step to consider when planning your tests, APEX DX and APEX DS make the process easier by offering more options to provide an easier path to data testing. No matter what A+D Device you use, APEX DS can interface with it to create the most robust (and space efficient!) data files for your tests, but should you choose to collect the data another way, APEX DX Data Acquisition Software will still be able to process your files with consistency.

 

 

If you are interested in streamlining your data collection and analysis process, please contact our sales team at info@apexturbine.com. We would love to talk with you about how we can help, and get you set up with a fully featured demo license, so you can see the difference for yourself.

 

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