EIS Data File Overview

An EIS software data file is a standard ASCII file. By default it has a .DTA filename extension. You may use other filename extensions, but they are less convenient.

The Windows® Notepad is a convenient editor that you can use to examine and modify EIS data files. However, it is limited to files shorter than 64 kbytes. Microsoft® Excel®, with its powerful text formatting, is the preferred tool for printing all data files and editing files too long for Notepad.


The EXPLAIN tag identifies this file as one output from an Explain™ script. Without this tag, a file is not read in by the Gamry Echem Analyst™.

The data file consists of data objects identified by types and tags. The type is a text descriptor of the type of object which should be created from this information. Each type begins a line in the file. Any text at the beginning of a line is assumed to be a type. The data objects can be of various types. One object, uniquely identified as type TAG, is used to specify which experiment created the data file. This is used by the Gamry Echem Analyst to determine which analysis script to use when this data file is opened.


After each type identifier, there is a TAG identifier. This tag is a unique name for a specific object. Setup parameter data objects have one or more values following the type and tag. In the following example, the tag of the object is VDC. The object is of type POTEN, and the information about the POTEN is contained in the following three fields.

POTEN VDC -5.00000E-001 F DC &Voltage (V)

One special type is a TABLE. A TABLE is output by a data curve. The tag for a data curve is followed by the entire data array.


Pt Time Freq Zreal Zimag Zsig Zmod Zphz Idc Vdc Irange

# s Hz ohm ohm V ohm ° A V #

0 7 5000 201.039 -33.332 1 203.784 -9.41393 8.89475E-006 0.005877 4

1 12 4032.26 198.969 -41.875 1 203.328 -11.885 4.45025E-006 0.004065 4

2 17 3205.13 201.301 -49.936 1 207.402 -13.9319 8.30867E-006 0.005587 4

Fields (tags and values) within data objects are separated by tabs. One exception is the separator between data points in a data curve, which is a carriage return. Notice that the fields do not always line up when the data file is printed or edited.

NOTE: Do not add spaces to the tabs separating the fields. Do not edit the data file with an ASCII editor that substitutes spaces for tab characters.

Data objects can appear in any order in the file. The Echem Analyst's GScripts locate objects within the file using their tags.