Hi Stephen,
I had this problem in the past.
Follow the Claes advice...
There is an example of how to make it possible to set priority on the plc. You probably have to to this every time you build the node.
> su
> ls -l plc_aristotle_0999_plc
-rwxrwxr-x 1 pwrp pwrp 6156906 Jul 5 13:25 plc_aristotle_0999_plc
> chown root plc_aristotle_0999_plc
> chmod u+s plc_aristotle_0999_plc
> ls -l plc_aristotle_0999_plc
-rwsrwxr-x 1 root pwrp 6156906 Jul 5 13:25 plc_aristotle_0999_plc
The real time priority can be displayed with ps, eg
> ps -eTo pid,pri,rtprio,comm
/Claes
I hope this solve your problem.
/Ben