Control Techniques Epsilon EP-P, Справочное руководство

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Epsilon EP-P Drive Reference Manual
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Revision A4 www.controltechniques.com
switch to the “called program”. In some cases it may be desirable to stop the screen from automatically changing to the “called
program”, this can be done by disabling (clearing) the Global Where Am I Enable check box. When clear, the Global Where
Am I feature will not function within the specific program. Each program has its own Global Where Am I Enable check box. By
default, all Global Where Am I Enable check boxes are selected (active).
Real Time Program View
The Real Time program is designed to be executed to completion in every update rate cycle. The real time program instruction
set is reduced to insure all the operations are completed within the update rate.
Figure 124: Real Time Programs View
Program Name
This is a 12 character string that the user can assign to an individual program. It allows the user to give a descriptive name to
the program for ease of use.
4.3 Program Multi-Tasking
Many applications require the operation of a background task that operates outside of the main program loop, but must be
consistently processed. For instance, a background task that performs calculations for values sent to an operator interface or
a background task that monitors parameters for fault detection.
The Epsilon EP-P processor has the ability to execute multiple tasks. Because only one task can be processed at a time, a
process called time slicing must be used. Time Slicing is simply splitting the total processing time between multiple tasks. The
processor stops all tasks and updates the control loop every 1600 microseconds (default, update time may be set by user).
Inside the control loop update, the drive updates the motion trajectory, captured data, digital inputs and outputs, and other
control parameters. Between each control loop update, the drive processes messages (i.e. Modbus, Ethernet, Faults, etc.)
and then runs as much of the user programs as possible until the next control loop update begins. Each update, a different
task is processed, and therefore how long it takes a given user program to complete depends how many tasks have been
created.
Figure 125: Time Slicing and Multiple Tasking Handling
The task assignment is done on the program view. Figure 123 shows the program view with the Task Number parameter. Use
the up and down arrows next to the Task Number to change the value. To create a new Task, simply click on the up arrow until
PowerTools Pro asks if you wish to create a new Task.
The Epsilon EP-P drive allows up to four different tasks in a single application.
T0 T1 T2 TN
Control Loop Update
Messages
Update Rate
User Program Execution