HI everyone,
I am writing here because I have a problem using a Real Time Controller (NI 3100 RT) in my application.
The controller is used to send a TCP/IP packet to a SCARA Robot controller that must receive an update every 8ms (this is the reason why I used the RT controller) and read the packet from the robot. A PC is connected by means of an ethernet cable to the RT controller, so the user can select the final position, the speed, etc. and visualize the position of the controller and the values of some load cells.
So the PC and the RT controller share some global variables (the end effector position, the value of the normal force,...).
The application works fine. The problem is that, after some minutes, the RT controller loses the connection with the robot, and from the robot I get the error message related to a packet delayed; so I guess that the VI had some problem to send the position update in 8 ms.
If i run just the VI on the RT controller, without launching the VI on the host PC, everything works fine; when the RT communicates with the PC, i get the timing error.
What can I do to solve this problem? In the RT controller vi I made two loops, an high priority one, to send the packets to the robot, and a low priority one for the communication with the PC, but the problem is still there. I also tried to modify the parameters related to the timed while loop (timeout, deadline, discard missed periods, mantain original phases), but without any good result (but if i uncheck the "Discard missed periods" box, the problem occurs less frequenty).
I attach some screenshots related to the target.vi, in particular the options related to the timing of the two loops, and how I implemented the low priority loop.
Another question: are there some options in the global variables section that can help me in solving the problem?
Every suggestion will be great,
Thank you very much to everyone.
Carmine
