DFQ Converter

Overview

The DFQ Converter reads measurement data in Q-DAS ASCII transfer format — the file extensions .dfq, .dfd, and .dfx — and outputs them as an Excel workbook. This allows you to open, inspect, and process data from measuring machines and CAQ systems without needing specialized evaluation software.

Your data stays with you: Your file is processed exclusively in working memory and discarded immediately after conversion — it is not saved or shared.

What is the DFQ format?

The Q-DAS ASCII transfer format was developed by Q-DAS GmbH (now part of Hexagon) and is considered the standard in the automotive and supplier industry for exchanging quality data. Measuring device manufacturers such as Zeiss, Mitutoyo, or Werth have their export interfaces certified for it.

AQDEF (Advanced Quality Data Exchange Format) is often used synonymously, but technically refers to something different: it is a certification profile of a working group of German automotive manufacturers that specifies which fields a measuring device manufacturer must support. The technical description of the format itself is found in the Q-DAS ASCII Transfer Format.

Structure of a DFQ file

A DFQ file consists of K fields. Each line begins with a key number, followed by the content separated by a space. The number after the slash indicates which part or characteristic the entry applies to:

K0100 2                     Total number of characteristics in the file
K1001 T4711                 Part number
K1002 Screw                 Part designation
K2001/1 M1                  Characteristic number of the first characteristic
K2002/1 Diameter            Characteristic designation
K2101/1 20                  Nominal value
K2110/1 19.6                Lower specification limit
K2111/1 20.4                Upper specification limit
K0001/1 20.03               First measurement value of the first characteristic

The key number determines what a field refers to:

Five fields must be present in every file for the records to be uniquely assigned: K0100 (total number of characteristics), K1001 and K1002 (part number and designation), and K2001 and K2002 (characteristic number and designation).

Tip: You do not need to know the K fields to use the converter. It automatically assigns them and labels the columns in the Excel file with plain-text names, for example K2110 Lower Specification Limit.

Supported formats and encodings

Input formats

Note: A .dfx file alone contains no characteristic designations and no limit values — these are in the associated .dfd file. If you upload a values file without its description file, you will get the measurement values but without labels.

Notations

The specification permits several equivalent notations, and measuring systems use them differently. The converter handles all of them:

• One field per line with characteristic number — K2002/1 Diameter
• Multiple characteristics in one line, separated by the control character $0F — K2002 Diameter¤Length
• Collective entry for all characteristics — K2142/0 mm sets the unit for every characteristic
• Values line by line without K fields, with additional data separated by $14
• Mixed notation within the same file

Character encoding

The default is Latin-1 (ANSI), which matches most files. If the file begins with a byte-order mark, the converter recognizes the encoding automatically and ignores the selection:

If umlauts or special characters are displayed incorrectly, the file has no byte-order mark and an encoding other than Latin-1. Then set UTF-8 or Windows-1252 and convert again.

What the converter does not do

• No export to DFQ. The conversion runs in one direction only: from Q-DAS format to Excel. DFQ files cannot be created from Excel or CSV data.
• No analysis. The converter reads and displays. Calculate capability indices afterward with the analysis modules of my8data, such as MSA or Process Capability.

The generated Excel file

The workbook contains up to six sheets. Empty sheets are omitted:

Encoded fields are translated: From K2004 = 1 becomes 1 (Attribute), from K2008 = 2 becomes 2 (Position tolerance).

Special features of measurement values

Measurements not performed. If a file contains placeholders with attribute 255, the cell remains empty and the row assignment is retained — the values in a row thus still belong to the same part. With attribute 256, the subsequent values shift because, according to the specification, part assignment need not be retained there.

Attribute characteristics. For count characteristics, the file contains no measurement value but sample size and number of defects. These appear as two separate columns. This also applies to defect summary cards and defect types.

Characteristic groups. Position tolerances and similar groups consist of a parent characteristic and the associated coordinates. The converter evaluates the structure information and assigns each characteristic to the correct part, even if a file contains multiple parts.

Validation

Each conversion is checked. The result is shown in the Validation sheet and also appears on the page:

If a file deviates so much from the standard that the conversion could be incomplete, the download is halted and the reason is displayed. Mere information about the file — such as missing optional fields or manufacturer-specific extensions — appears only as a note and does not stop anything.

Troubleshooting