Colyton Industrial Marking Solutions
design and manufacture custom marking solutions for industrial marking requirements We work with ID-Integration Inc. in the US to provide a comprehensive solution to your UID marking problems.Data Matrix Codes
Data Matrix Codes
A Data Matrix code is a two-dimensional matrix barcode consisting of black and white "cells" or modules arranged in either a square or rectangular pattern. The information to be encoded can be text or raw data. Usual data size is from a few bytes up to 2 kilobytes. The length of the encoded data depends on the symbol dimension used. Error correction codes are added to increase symbol strength: even if they are partially damaged, they can still be read. A Data Matrix symbol can store up to 2,335 alphanumeric characters.
Data Matrix symbols are rectangular in shape and usually square, they are made of cells: little elements that represent bits. Depending on the situation a "light" module is a 0 and a "dark" module is a 1, or vice versa. Every Data Matrix is composed of two solid adjacent borders in an "L" shape (called the "finder pattern") and two other borders consisting of alternating dark and light "cells" or modules (called the "timing pattern"). Within these borders are rows and columns of cells encoding information. The finder pattern is used to locate and orient the symbol while the timing pattern provides a count of the number of rows and columns in the symbol. As more data is encoded in the symbol, the number of cells (rows and columns) will increase. Symbol sizes vary from 8×8 to 144×144.
Applications
Data Matrix codes are part of a new traceability drive in many industries, particularly aerospace where quality control is tight and a black market exists for counterfeit or non-serviceable parts. Much of the Aerospace Industry, especially members of the Air Transport Association (ATA), are working on a tight deadline to have all components of every new aircraft identified by Data Matrix codes.
The US Department of Defense has selected Data Matrix for the mandatory unique identification (UID) of certain assets it procures for all of the services. Items from individual weapons to critical components of major systems must be permanently marked with a unique data matrix code in accordance with standards in Military Standard 130.
Data Matrix codes are becoming common on printed media such as labels and letters. The code can be read quickly by a scanner which allows the media to be tracked, for example when a parcel has been dispatched to the recipient, or can be used to control automated machinery to direct the parcel to its destination.
For industrial engineering purposes, Data Matrix codes can be marked directly onto components, ensuring that only the intended component is identified with the Data Matrix encoded data. The codes can be marked onto components with various methods, but for permanent marking, dot-peen marking, laser marking, and electrolytic chemical etching (ECE) are the preferred methods giving a permanent mark which should last the lifetime of the component. In the motor industry they are used to identify not just the component but the machines that manufactured the component and the date. This allows the manufacturer to identify all the vehicles fited with components from a specific machine on a specific date which gives much tighter control over quality.
After creation of the Data Matrix code, the code is usually verified using specialist camera equipment and software. This verification ensures the code conforms to the relevant standards, and ensures it will be readable for the lifetime of the component. After the component enters service, the Data Matrix code can then be read by a reader camera, which decodes the Data Matrix data which can then be used for a number of purposes, such as movement tracking or inventory stock checks.
The data matrix code is particularly useful where the components are subject to corrosion or damage as the redundancy in the code allows data t obe recovered even from damaged codes.
Technical Specifications
Data Matrix symbols are made up of modules arranged within a perimeter finder and timing pattern. It can encode up to 3,116 characters from the entire ASCII character set (with extensions). The symbol consists of data regions which contain modules set out in a regular array. Large symbols contain several regions each of which is delimited by a finder pattern, and this whole symbol is surrounded on all four sides by a quiet zone border (margin). The finder pattern takes up two sides of the matrix allowing orientation of the code to be determined. The other two sides of the code are made up of the timing bars which are alternate 0's and 1' identifying the positions of the individual modules of the matrix.
The modules may be round or square- no specific shape is defined in the standard. For example, dot-peened cells are generally round however the AIM specification effectively requires square modules as dot peened marks will grade as an F when viewed with a reader setup to correctly read to the AIM specification. The AIQG specification is more appropriate for dot peen marks.
Symbols have an even number of rows and an even number of columns. Most of the symbols are square with sizes from 10×10 to 144×144. Some symbols however are rectangular with sizes from 8×18 to 16×48. All symbols utilizing the ECC200 error correction can be recognized by the upper right corner module being the same as the background color. (binary 0).
ECC200 is the newest version of Data Matrix and supports advanced encoding error checking and correction algorithms (such as Reed-Solomon). ECC200 allows the routine reconstruction of the entire encoded data string when the symbol has sustained 30% damage, assuming the matrix can still be accurately located.
Standards
Data Matrix was invented by International Data Matrix, Inc. (ID Matrix) which was merged into RVSI/Acuity CiMatrix, who were acquired by Siemens AG in October, 2005 and Microscan in September 2008.
Data Matrix is covered today by several ISO/IEC standards and is in the public domain for many applications, which means it can be used free of any licensing or royalties.
* ISO/IEC 16022:2006 Data Matrix bar code symbology specification
* ISO/IEC 15415 2-D Print Quality Standard
* ISO/IEC 15418:2009 Symbol Data Format Semantics (GS1 Application Identifiers and ASC MH10 Data Identifiers and maintenance)
* ISO/IEC 15424:2008 Data Carrier Identifiers (including Symbology Identifiers) [IDs for distinguishing different bar code types]
* ISO/IEC 15434:2009 Syntax for high-capacity ADC media (format of data transferred from scanner to software, etc.)
* ISO/IEC 15459 Unique Identifiers
The majority of readers work to both the AIM standard which is designed around the use of square dots, and is particularly aimed at laser or chem etch marking. The use of dot peen markers results in round dots and an new standard was introduced by the AIQG to cover reading of Data Matrix codes made up of round dots.