Mitsubishi Q2ACPU, User Manual

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App - 121
APPENDICES
Appendix 4.4 Timer and Interrupt Counter Operations
(1) Timer
(a) The ACPU turns timer coils ON/OFF on execution of the OUT instruction, and
updates timer current values and turns contacts ON/OFF on execution of the
END instruction. In contrast, the QnACPU turns timer coils ON/OFF, updates
current values, and turns contacts ON/OFF on execution of the OUT instruction.
Note that after conversion, the turning of contacts ON/OFF may be up to one
scan faster.
Example: Timing for turning contact ON
In the case of ACPU, a timer contact will turn ON quickly if it is located in the first
step. In the case of QnACPU, it will turn ON quickly if it is located in the step
following OUT T.
(b) Note that processing differs as follows when the set value of a timer is set to K0:
• For ACPU, count is in infinite units (timer does not count up).
• For QnACPU, the timer counts up instantaneously.
(2) Interrupt counter
Interrupt counters for QnACPU count the number of interrupt occurrences. However,
the counter contact does not turn ON even when the count has reached the set
value.
The operation of interrupt counters for ACPU differs according to the CPU type.
(a) Interrupt counters for A3HCPU, AnACPU, or AnUCPU count the number of
interrupts occurrences. When the count reaches the set value, the counter
contact turns ON.
In order to achieve the same operation as with interrupt counters for A3HCPU,
AnACPU, and AnUCPU when using a QnACPU, the program must be modified
after conversion.
An example modification is shown below.
(b) Interrupt counters for AnCPU and AnNCPU operate as counters used in interrupt
programs.
To achieve the same operation as with interrupt counters for AnCPU or AnNCPU
when using a QnACPU, the program modification is not needed after
conversion.
When ordinary counters are used in an interrupt program with QnACPU, they
operate in the same way as with AnNCPU.