Control Techniques Epsilon EP-P, Reference Manual

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Epsilon EP-P Drive Reference Manual
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www.controltechniques.com Revision: A4
The following two figures are timing diagrams of a cyclic program with different utilization values (showing the effect) and a user program
initiated to run on several tasks.
Figure 130: Diagram of User Programs on Two Tasks and a Cyclic Program
Figure 131: Diagram of User Programs on Three Tasks and a Cyclic Program
The 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 132: Diagram of User Program and a Real Time Program
T0
Control Loop
Cyclic Program
Update Rate
User Program T1
T0
Cyclic Update = 3x Update Rate
T1 T0
T1
Control Loop + Cyclic Prog + User Progs on two Tasks. Cyclic
Program Utilization set to 70% means cyclic program is suspended
after 70% of update is reached, then resumed next update Cyclic Program Utilization
set to 70%
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
Real Time Program
Update Rate
Control Loop + Real Time Prog + User Prog on one Task
User Program
T0 T0 T0 T0 T0