Labview remote control and data transcation

Question

Hi,
We have a complicated timing control system written in labview
6.1 running on our lab PC-1.  Since it is not easy to upgrade to a most
recent version and limited PCI-slots, and we need to add a few device
control programs (written in C++ or updated labview), we are thinking of
an ultimate control system with two PCs and let the old timing program
be a "slave" of "master" computer PC-2.  OS for both PCs are windows XP.
The communication between the two PCs are
fairly straight forward: suppose on PC-1, the program breaks into two
parts: part A and part B. PC-2 sends selection messages to PC-1 to
determine which part needs to be running during a particular shot. It is
true that to our best interest we might need  PC-2 to send data to
PC-1, in case for a particular run we have to change some data values of
timing program. 
The problem might appears to be a piece
of cake to you experts. It is worth mentioning that on PC-1, any
changes made to the timing program is nontrivial due to its structual
complexity. The program is DAQ based (finite) pattern generation (using a
lot of PCI 6534/PCI 6713/counters, external clocking). 
The
reqiurement for speed is not high. PC-2 can in general wait for 1
second before PC-1 receives a message and start to output.   On the
other hand, the smaller the delay, the better. 
We have
considered a few communication options like TCP/IP, RS232 ports, etc. 
But before we start implementing the changes, we would really appreciate
your suggestions/comments! 
Thanks very much in advance
for your time! 
Kunyan

Answer 1

Kunyan,
there are really several different ways to solve this. The major question is: Is this a handshake protocol or simple "notifications"?
If it's simple notifications, things are getting quite easy.
You can use TCP/UDP/DataSocket/STM if there is a network connection between both PCs. Otherwise, RS232 might be a good idea as well for sure.... but i suggest a network technology in order to reduce delays.
STM is a protocol built up on TCP and even if you do not use it (it is not available for LV 6.1!), it might get you some ideas about defining a custom protocol.
hope this helps,
Norbert
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