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.