labview remote control and data transcation

[eLions]

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

[Norbert_B]

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

[eLions]

Thank you, Norbert.

To our best interest, we might need to pass parameters from PC-2 to PC-1, this will give us full controllability. However we will work to the extreme that we transfer least parameters possible. 

The two PCs are connected via our department server, we might need to remote monitor two PCs in real time, which limit use of internet interface. 

Could you briefly describe a few methods or protocols?   

Thanks again for yout help!