This module is used mainly to compare channels of measurement data in a fast and convenient way, MMFD displays files as graphs. Single files are also easily displayed. Up to 32 files can be plotted, either separately, or at up to 8 files per page. Files can be overlaid (superimposed) on a single set of axes, or even cross plotted against each other to test correlation. Scaling, tracking and scrolling functions are available. To invoke this program from the system prompt type mmfd.

The MMFD module can display several data files simultaneously. It is intended primarily to display time series data such as single parameter .dac files, however, other data files with a single parameter structure can also be displayed.

As stated earlier, up to 32 data files may be plotted during a single run of the program. The plots may be presented either separately or overlaid. In this way data from a particular measurement campaign can be easily compared and contrasted.

To aid the process of comparison, the Y-axes of the displays can be scaled in any one of three ways:

There are three types of plots that can be displayed:

In cross-plot mode, there are facilities to setup exclusion zones, adjust plotting resolution and slow down plotting by time delay to aid in the viewing (and plotting) of data.

In standard and overlay modes there are facilities for scrolling through the data and tracking individual data sets for coordinate values to aid in the viewing of data.

MMFD can display the contents of a single data file or a group of files. The concept of a generic name for a test represents a quick method of entering channel names for processing. The methodology is based on the fact that data derived from the same test, are usually demultiplexed into individual channel files whose file name structure consists of a generic base (test) name, normally the name of the multiplexed data file itself, with the appropriate channel number appended. For example, if the name of the multiplexed data file happened to be DATA, then the following file names would be generated: data01.dac, data02.dac,..., datann.dac.

In the above example, the generic name of the test would be data. So entering data(1-n) where n is the last number in the series will process all files prefixed by the word data. If fewer files exist than are specified then MMFD will display an error message prompt to that effect and proceed to display the data files that do exist.

Since MMFD expects to process standard time series data files (usually a .dac file) the above generic test name convention only applies to this data type. Files with the correct internal format but different file extensions, such as spectra with the extension .psd, must have their names entered in full, i.e. including the file extension e.g. data(1-n).psd.

MMFD expects to find the data files for plotting to be resident in the user’s directory, however, other directories can also be accessed if the complete file specification i.e. path name and file name are entered.

If data files unconnected by a generic test name are to be processed then enter their full file names separated by commas.

A very easy way to select files is by using the List facility. List displays all available files on a scrollable pick list. Files on the list can be selected by pointing and clicking with the mouse pointer. For technical reasons the files picked from this list are not remembered once you have progressed beyond this screen, although the path is remembered and used in the next run of the program.

If more than 1 individual file name is typed then the last name in the list is saved to the environment and is used as the default file name the next time the program is run. Also files that are typed are remembered once you have progressed beyond this screen but return to it. Files must be separated by commas.

Up to 32 individual file names may be entered.

When the files have been selected, MMFD will display either the names of the files or the number of files selected.

Generally speaking, as a default, MMFD will plot the entire contents of each data file separately on the screen and scale each data set to its own local maximum and minimum values. If something other than these defaults are required, then answer this question YES. Having requested to alter the default settings up to 8 additional fields will be displayed.

Graphical display operations in MMFD are similar if not identical to that of PTIME. These operations and the description of pull down menu options are described in Plot an Entry Option, 217.