138
Epsilon EP-P Drive Reference Manual
www.controltechniques.com
Revision: A4
Dwell For Master Dist
Wait For (XXXX)
The motion related instructions will only block the task for the remainder of the current update and the task will operate normally the next time
it is processed. However, because the drive can currently only process one motion command at a time, a buffered motion command could
cause the program to be blocked for a longer period of time.
For instance, if a program initiates Index0 and the next program instruction initiates Index1, the program will be blocked until Index0 is
complete. This is because Index1 cannot start until Index0 is finished.
A Dwell instruction is also a motion instruction and can block the program in the same way. The Dwell cannot start until Index0 is complete,
and therefore the program (or task) is blocked until Index0 is finished.
The Wait For instruction will block the program until the Wait For condition is satisfied. The Wait For condition does not have to be TRUE at the
exact time the task is processed. If the Wait For condition is satisfied at any time (even when that task is not being processed) the task will be
scheduled to run the next time through the loop.
Figure 142 shows the same time-slicing diagram as the previous figure, but Task 0 is blocked in this example. Notice how Task 0 is skipped
when the processor recognizes the task is blocked and processor execution switches to Task 1.
Figure 142:
Block Time Slice
The time taken to process the blocked task and pass on to the next available task is between 50 and 100 microseconds.
Figure 143 is a flowchart that reflects the time-slicing process. It shows the complete loop based on whether Modbus messages need
processing and if programs (tasks) are blocked.
Blocked here until
Index0 is complete
Index.0.Initiate
Index.1.Initiate
DriveOutput.1=ON
Blocked here until
Index0 is complete
Index.0.Initiate
Dwell For Time 1.000 'Seconds
ModuleOutput.1=ON
T
ask 0
T1
T2
T3
T4
Control Loop Update
Messages
Update Rate
User Program Execution
= Control Loop
= Messages (Modbus, Ethernet, Faults, etc.
= Program Execution
= Blocked Task (Blocked Program)
Содержание Epsilon EP-P
Страница 2: ......
Страница 14: ...xii Epsilon EP P Drive Reference Manual www controltechniques com Revision A4 Glossary 225 Index 231...
Страница 124: ...110 Epsilon EP P Drive Reference Manual www controltechniques com Revision A4...
Страница 200: ...186 Epsilon EP P Drive Reference Manual www controltechniques com Revision A4...
Страница 218: ...204 Epsilon EP P Drive Reference Manual www controltechniques com Revision A4...
Страница 238: ...224 Epsilon EP P Drive Reference Manual www controltechniques com Revision A4...
Страница 244: ...230 Epsilon EP P Drive Reference Manual www controltechniques com Revision A4...
Страница 247: ......