6. Function blocks
6.2 Interrupt function blocks
 Device inputs
 I01 I02 I03 I04 I05 I06 I07 I08
CH03 high-speed
meter


x





CH04 high-speed
meter



x




CI01 incremental
counter
x
x






CI02 incremental
counter


x
x




IE01…IE08
One input, I01 – I08 can be assigned freely (max. 8, none can be assigned more than
once)
IC01 – IC08
Two inputs, I01 – I08 can be assigned freely (max. 8, none can be assigned more than
once)
IT01…IT08
Automatically assigns the user interrupts 1 to 8 that are still available (only for
instances of I01 – I08 that are not in use by other function blocks)
The time between the moment the triggering signal is detected and the moment there
is a response at an output is < 1 ms. If multiple interrupts are executed sim-
ultaneously, the times add up.
Measuring the interrupt load
The runtime for each interrupt source is measured in µs. All measured times are
added over a period of 100 ms. After each 100 ms, the total of all times is evaluated
and the time measurement is cleared. If the interrupts used up more than 50% of the
computing time, the application will be stopped.
The <System_CPU_overload> diagnostic message will be generated and ID19 will be
set to 1.
For more information on how diagnostic messages can be called and processed,
please refer to
Available fixes for high interrupt loads
If the interrupt load becomes too heavy, the following steps can be taken to reduce it:
l
Reduce the number of function blocks
l
Keep the interrupt routine as short as possible
l
Reduce frequencies when using counters
Example of a time-controlled interrupt function block in easySoft 8
Output Q4 needs to be reset after a specific time. This time should be independent
from the main program's cycle time so that the switch-off point in time is always the
same.
586
easyE402/24 MN050009ENEaton.com
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