The details of producing "near-live" graphs

version 1.0 June 02 1996: Black and white graphs via .PIC files
version 1.1 June 10 1996 : Color graphs via HPGL printing
version 1.2 March 18 1997 : ISDN DosPPP transfer

version 2.0   25 January 1998: 7 days graphs + UVI computation

Francis Massen, LCD

As can be seen from the chart the technical backbone of Meteo_LCD is a net of old faithful 80286 Bull Micral and one 486 Z-Station computers. All software is exclusively DOS based, the Lan hard- and software being Dlink's DE220CT Ethernet cards and the Lansmart Peer-to-Peer NOS.

A major (if not dominant!) role is played by the AUTOMITE Pro scheduler from the Pendulum Group Inc. This marvellous scheduler can play back any sequence of keystrokes, with all the needed wait times. A Graesslin DCF77 radio-controlled ("atomic") clock is used for making the hard on/off switchings to bring the whole system into a well defined state at every hour.

Extracting the necessary data and making the "near-live" graphs is a multi-step procedure:

Every hour at xx:02 (less frequently at night(!) and late afternoon) the DCF77 clock powers down the meteo computer for 10 seconds, to assure that the system is always in a well defined state. At xx:15 the Automite scheduler downloads all new data from the last download on. These "fresh" data are appended to a file called TODAY.DAT. From TODAY.DAT extract a subset TODAY_X.DAT (temp, Solar Rad., UVB, Ozone...),   and extract from LCD_UV.DAT a subset of the last 7 days. All files are now copied over the LAN to the modem server and ISDN servers. The modem server runs in host mode waiting for a call (Telix Hostplus is used; access is restricted to qualified collaborators), the ISDN server makes the uploads to our ISP. All data file management is done with macros of Semware's famous E editor.

At xx:25, a second copy of Automite running on the ISDN server starts the following sequence of events:

  1. call a Quattro Pro spreadsheet and execute 8  macros which build the graphs, and print them as a HPGL file into files
  2. call a conversion process to convert the .HGL --> .PCX --> .GIF, using Printgld from Ravitz Software to make the conversion HGL-->PCX and a freeware utility cvt2gif to convert PCX --> GIF
  3. execute KlosPPP + WatFTP to make an automatical ftp to the Internet via an ISDN line, using an external Zyxel Elite 2684I "modem". (see the relevant paper).

Printing the graphs into a HPGL file is the only method we found to obtain coloured graph files. The capability to convert HPGL --> PCX is a rare feature which we found only in the extremely well done Printgl software.

If you have implemented similar features, or if you just want to give your opinion, we appreciate all comments and suggestions!

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