Product: ISaGRAF V3
Date : 5-March-1996
File : Pcmulti.Multi target communication on a PC platform.htm
Subject: Multi target communication on a PC platform
Remember that you cannot run more than 1 ISaGRAF Kernel on
monotasking MS-DOS system. Multiple applications on a PC will
require a multi-tasking system (for example Windows NT).
In this case, it is possible to share the same IO board. This is
done by the IO driver. It means that the IO driver C code has to
take all the precaution to share access to the same physical IOs.
Generally, you will have to add dedicated parameters to IO boards,
in order to handle the priority between different ISaGRAF
applications, mainly for outputs! Doing this, you can for example
enable or disable the physical access by one ISaGRAF kernel to one
physical IO, according to its priority.
The IO driver designer has to establish this priority system.
Nothing is packaged by ISaGRAF kernel.
Variables used by different ISaGRAF kernels can be shared using the
IO interface (it meens they are IO variables) or by using the server
access. Even in this case, each ISaGRAF kernel has its own copy of
the variable state in its data base. The same principle can be
applied to multiple ISaGRAF kernels located on different nodes of a
network. Some of our customers in Europe already implement such
things with FIP or ProfiBus protocols.
Copyright © 1996-2009 ICS Triplex ISaGRAF Inc. All rights reserved.