Control Techniques UD70, User Manual

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UD70
Issue code: 70nu2
Reference 7-1
7 Reference
7.1 Tasks
Refer also to Tasks and real-time programming in Chapter 4
DPL Programming.
INITIAL task
The
INITIAL
task is used typically to initialize program variables and Drive
parameters.
The
INITIAL
task boots-up the DPL program and runs only when the
UD70
is
reset or at the moment
AC
power is applied to the Drive.
The
INITIAL
task is special in that all other tasks are guaranteed not to be
running when it is being run. This is significant when other real-time Tasks
are to manipulate data which have initial values.
BACKGROUND task
The
BACKGROUND
task is used for functions and commands that do not
require time-related or encoder-related monitoring. It would be used for
the following:
•
Data logging
•
Checking digital inputs
•
Setting output status
The
BACKGROUND
task runs after the
INITIAL
task is completed. It is
recommended that the majority of the program is run in the
BACKGROUND
Task.
Note
The
BACKGROUND
task does not automatically loop.
Example BACKGROUND{
RAMP:
#1.21 = 0
DO WHILE #1.21 < 1000
#1.21 = #1.21+1
LOOP
GOTO RAMP:
}