I have a single ZADR820ProXR_ETHER board connected to four Win7 PC’s.
Each PC runs a copy of a C# program (which I have source code for).
Each program controls a distinct subset of the relays on the ProXR.
Each program opens a virtual com port (Digi RealPort), sends a command
to the ProXr (as tcp/ip) and closes the virtual com port.
Normally this works, but occasionally two of the PC’s try to access
the ProXR at the same time and both programs fail, throwing
System.IO.IOException: A device attached to the system is not functioning.
Is this to be expected or am I doing something wrong?
As a work around, I have “time sliced” the four programs such that
the first only talks to the ProXR during seconds 0-12 of each minute,
the second talks during seconds 15-27, the third 30-42 and the fourth
45-57. This works at the cost of slower execution.
Can you suggest a better way?