IMCtermite provides access to the proprietary data format IMC Bus Format with file extension .raw introduced and developed by imc Test & Measurement GmbH. This data format is employed i.a. by the measurement hardware imc CRONOSflex to dump and store data and the software packages imc Studio and imc FAMOS for measurement data control and analysis. The extracted measurement data can be stored in various open source file formats like csv, json, parquet or hdf5.
Overview
Fileformat
A data file of IMC Bus Format type with extension .raw is a mixed text/binary
file featuring a set of markers (keys) that indicate the start of various blocks
of data providing meta information and the actual measurement data. Every single
marker is introduced by character "|" = 0x 7c followed by two uppercase letters,
which characterize the type of marker. Each block is further divided into several
parameters separated by commata "," = 0x 2c and terminated by a semicolon
";" = 0x 3b. For instance, the header - first 600 bytes - of a raw file may
look like this (in UTF-8 encoding)
|CF,2,1,1;|CK,1,3,1,1;
|NO,1,86,0,78,imc STUDIO 5.0 R10 (04.08.2017)@imc DEVICES 2.9R7 (25.7.2017)@imcDev__15190567,0,;
|CG,1,5,1,1,1; |CD,2, 63, 5.0000000000000001E-03,1,1,s,0,0,0, 0.0000000000000000E+00,1;
|NT,1,16,1,1,1980,0,0,0.0; |CC,1,3,1,1;|CP,1,16,1,4,7,32,0,0,1,0;
|CR,1,60,0, 1.0000000000000000E+00, 0.0000000000000000E+00,1,4,mbar;|CN,1,27,0,0,0,15,pressure_Vacuum,0,;
|Cb,1, 117,1,0, 1, 1, 0, 9608, 0, 9608,1, 2.0440300000000000E+03, 1.2416717060000000E+09,;
|CS,1, 9619, 1,<2C>oD <09>nD6<44>nD)<29>nD<6E>
where line breaks where introduced for readability. Most of the markers introduce
blocks of text, while only the last one identified by |CS contains binary data.
The format supports the storage of multiple data sets (channels) in a single
file. The channels may be ordered in multiplex mode (ordering w.r.t. time) or
block mode (ordering w.r.t. to channels).
The markers (keys) are introduced by "|" = 0x 7c followed by two uppercase
letters. There are two types of markers distinguished by the first letter:
- critical markers: introduced by
|Cfeaturing uppercaseC - noncritical markers: introduced by
|Nfeaturing uppercaseN
The second letter represents further details of the specific key. Note, that
while the noncritical keys are optional, any .raw file cannot be correctly
decoded if any of the critical markers are misinterpreted, invalid or damaged.
The second uppercase letter is followed by the first comma and the version
of the key starting from 1. After the next comma, an (long) integer (in text
representation) specifies the length of the entire block, i.e. the number of
bytes between the following comma and the block-terminating semicolon. The further
structure of a block is not defined and may feature different numbers of additional
parameters. The format allows for any number of carriage returns (CR = 0x0d)
and line feeds (LF = 0x 0a) between keys, i.e. the block terminating semicolon
and the vertical bar (pipe) of the next key. The following critical markers
are defined
| marker | description |
|---|---|
| CF | format version and processor |
| CK | start of group of keys, no. parameters = 3, indicates (in)correct closure of the measurement series |
| CB | defines a group of channels |
| CT | text definition including group association index |
| CG | introduces group of components corresponding to CC keys |
| CD1,2 | old/new version of abscissa description |
| CZ | scaling of z-axis for segments |
| CC | start of a component |
| CP | information about buffer, datatype and samples of component |
| Cb | buffer description |
| CR | permissible range of values in component |
| CN | name and comment of channel |
| CS | raw binary data |
| CI | single numerical value (including unit) |
| Ca | add reference key |
Among the noncritical markers, there are
| marker | description |
|---|---|
| NO | origin of data |
| NT | timestamp of trigger |
| ND | (color) display properties |
| NU | user defined key |
| Np | property of a channel |
| NE | extraction rule for channels from BUS data |
The format loosely defines some rules for the ordering of the markers in the file stream. The rules for critical keys include: CK has to follow up on CF, CK may be followed by any number of CG blocks, each CG has to be followed by (any number of) component sequences comprised of the series CC , CP, (CR), (ND) and terminated by either CS or the start of a new group, component, text field or buffer.