Programme DMMtr.OPL for PSION 3c (operating system EPOC-16)
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Using the PSION 3C as a data display and recorder for a VOLTCRAFT 
digital multimeter. Other instruments with a serial interface may 
be used after making the appropriate changes in the transfer protocol.

Connect the multimeter to the PSION 3c by means of the serial cable 
and an easy-to-make adapter. Instructions for making the adapter are 
contained as a HELP-window in the code. PLEASE NOTE: any electrical
hook-up of the PSION with an external device are your own responsi-
bilty. I decline any liability whatsoever, as I have no control over
the circumstances under which these manipulations are done.

The programme was thoroughly tested with the multimeter VOLTCRAFT 
M3850D. 
 
Some noteworthy features:

-- All input parameters are stored in a separate DMMTR.INI file, 
   located in \APD\. They are fully explained in HELP windows. This 
   file is generated by DMMtr if it does not yet exist.

-- Selection of 16, 40, 80, 200 or 400 measurement points per screen.

-- Up to 999 screens can be automatically filled.

-- Measurements are either manually or automatically triggered. 

-- Recordings start only after valid data are detected.

-- Graphs may be stored as bitmap files (PSION .PIC format). The 
   structure of the bitmap file is explained in a HELP window to 
   facilitate writing one's own reading codes. A public domain source 
   code for reading such bitmaps is: 
      ftp://ftp.mathworks.com/pub/contrib/v5/image/PicRead.m 

-- Data may be stored in a text file for subsequent numerical 
   processing, e.g. by importing the data into Microsoft-Excel; these 
   recordings run in parallel to the build-up of the graph. The format 
   of the data file is explained in a HELP window. Its structure allows 
   direct access by vector graphic programs such as GNUPLOT and many 
   others. As a text file with ASCII coding it can be edited with any 
   text editor. 

-- Unique names for the graphic files (DMMTRxxx.PIC) and data files 
   (DMMTRxxx.DAT) are automatically generated. They are located in \OPD\. 

-- Arbitrary limits of the ordinate of the graph can be entered. 
   These limits do not apply to the data file. The ordinate can be 
   either unipolar from zero to Y(max) or bipolar from -Y(max) to 
   +Y(max). 

-- Overflows are indicated; they do not corrupt the graph. 

-- The time stamp of the beginning of the measurement series with valid 
   data is printed on the graph and stored in the optional data file.

-- The temporal interval between measurements may be chosen in steps of 
   0.1 seconds between 1.2 seconds (limit set by the multimeter) and 
   one week.  

-- The measurement units as well as the sampling interval are printed 
   on the graph. 

-- The autoranging feature of the multimeter is compensated so that
   automatic range changes during a measurement run do not alter the 
   measurement unit either on the screen or in the data file.

The system VOLTCRAFT + PSION 3C + Software is characterised best as a 
small lightweight data recording system for slowly varying processes. 
Because of its low power consumption it is particularly suited for 
observations in the field of processes which are slow, have long 
(even years!) duration and for which electrically readable sensors 
are available.  

List of files:

-- DMMtr.opl ......... source file;
-- DMMIcon.pic ....... icon; place it into the directory \APD\;
-- DMMtr.txt ......... this text file;
-- DMMtr1.pic ........ an example of a saved screen;
-- DMMtr1.dat ........ an example of an alphanumeric data file

The whole works is FREEWARE. Comments, bug reports and suggestions 
for improvements are most welcome.

Peter M. W. Nave', 100010.3276@CompuServe.com, 1998-09-01.
