FX Series Programmable Controlers Applied Instructions 5
5-113
e) Users of all PLC models have the option of allowing interrupts to occur immediately, i.e. during
the operation of the FROM/TO instructions or to wait until the completion of the current FROM/
TO instruction. This is achieved by controlling the special auxiliary flag M8028. The following
table identifies certain points associated with this control and operation.
Users of FX
1S have no option for interruption of the FROM/TO instructions and hence
always operate in a mode equivalent to having M8028 switched OFF.
Interruption Disabled Interruption Enabled
M8028 = OFF M8028 = ON
Jumps called by interrupt operation are delayed
until the completion of the data transfer of the
FROM/TO instruction
Jumps called by interrupt operation occur
immediately
A small delay of (800m +200) µsec can be
expected in the worst case. Note: m = the number
of 32 bit words
Data transfer will resume upon return from the
interrupt program. This may not be desirable if a
FROM/TO instruction has been programmed
within the called interrupt
Ensures that FROM/TO instructions included in
an interrupt program will not interact with others
elsewhere
M8028 should only be used when a very short
delay is required in applications where timing and
accuracy’sareimportant
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