Danfoss MCO 305 Design Manual page 163

MCO 305 Design Guide
ON INT / ON COMBIT / ON STATBIT
If two (input) interrupts occur simultaneously, then the one with the lower number is executed first,
however the other is not lost. After the interrupt procedure is completed the other is called up
accordingly.
If the same input or interrupt occurs again while the procedure is being executed this is noted again and
subsequently executed.
Thus, an interrupt can only be lost if it occurs twice during the execution of an interrupt procedure.
ON TIME / ON PERIOD
As described above the execution time for every temporal function is stored in an internal structure. For
simultaneous execution times the procedure that is first on the list will be executed first. The priority is
thus determined by the sequence of the ON PERIOD commands.
ON PARAM
If several of these interrupts occur simultaneously, they are processed according to the sequence of the
ON PARAM commands in the program.
Interrupt Nesting
It is not possible for one interrupt to be suspended by another. Accordingly, while one interrupt is being
processed a second interrupt cannot be processed. The only exception is the ON ERROR function, which is
also possible during the processing of interrupts.
However, an ON ERROR function cannot be suspended by an interrupt.
NOWAIT in Interrupts
In general, during an interrupt NOWAIT is set to ON, that means that the program does not wait for the
completion of POSA commands.
This is necessary since otherwise a POSA command cannot be suspended by an interrupt procedure, since
this would immediately wait for the arrival of the axis. Thus, if you wish to wait for the arrival of an axis
during an interrupt procedure, this must be done explicitly with WAITAX.
Elements of the Programming Language
APOSS Number Formats
16
Word (16 bit): 2 - 1 = 65535
31
Long word (32 bit): -2
Positions (32 bit, where 1bit is used to handle overflow):
30 30
-2 to +2 -1 corresponding to -1073741823 to + 1073741823
Jumping from position 1 billion to position –1 billion
when positioning or synchronizing is handled
bumpless by the controller and no pulses are lost.
__ How to Program __
31
to +2 -1 = -2147483648 to + 2147483647
®
MG.33.L5.02 – VLT
Position
30
2 -1
30
-2
is a registered Danfoss trademark
Time
163