Emerson EZMotion - Page 168

156 EZMotion User/Programming Guide
www.controltechniques.com Revision: A8
Figure 164: Diagram of User Programs on Three Tasks and a Cyclic Program
The next two figures show how the Real Time program is executed prior to the user program and how the size of the Real Time
program effects the time left in the update rate for the user program to complete.
Figure 165: Diagram of User Program and a Real Time Program
Figure 166: Diagram of User Program and a Real Time Program
T0
Control Loop
Cyclic Program
Update Rate
User Program
T1
T2
Cyclic Update = 3x Update Rate
T0 T1
T2
Control Loop + Cyclic Prog + User Progs on three Tasks. Note how
when the number of Tasks is the same as the Cyclic Program
Update Rate setting, some programs get shortchanged. This
should be avoided by changing the Cyclic Program Update Rate
Cyclic Program Utilization
set to 70%
T0
Control Loop
Realtime Program
Update Rate
Control Loop + Realtime Prog + User Prog on one Task
User Program
T0
T0 T0
T0 T0
User program can be "choked" if too much code is put into
realtime program
Control Loop
Update Rate
User Program
Realtime Program