CAL Poll Version 1.0     28/Oct/1999

    This file contains some basic information
about the CAL Poll application. The application
and associated source files are provided as an
example of ModBus communications over RS232
(or RS485 using a suitable adapter).

    The application contains two source modules
which deal with the communications tasks,
CommsDevice and ModBus. These two modules
contain additional documentation regarding
their operation.

    The CAL Poll application was created using
Microsoft Visual C/C++ 6 and uses the Win32 API
to interface to the communication resources
under Windows 95,98 and Windows NT.

    The CAL Poll application itself is a simple
communications program which will scan a specified
range of ModBus addresses on the specified
communications interface and list the CAL
instruments detected.
    The status of these instruments can then
be displayed and will show the current temperature,
the display LED's and the current set point value.
The set point value can then be changed using the
set button.
    This gives an example of reading from, writing
to and program mode operations on CAL instruments.

Visual C/C++, Windows 95,98 and NT are trademarks of
Microsoft Corp.
ModBus is a trademark of AEG Scheider Automation.