Mitsubishi Q02CPU

9
DEVICE EXPLANATION
9.2 Internal User Devices
9.2.11 Counter (C)
9
- 36
9
Device Explanation
10
CPU Module Processing Time
11
Procedure for Writing Program to CPU Module
AppendicesIndex
(4) Interrupt counters
(a) Definition
Interrupt counters are devices which count the number of interrupt factor
occurrences.
(b) Count processing
1) When interrupt occurs
The interrupt counter's current value is updated when an interruption occurs. It
is not necessary to create a program which includes an interrupt counter
function.
2) Counting of interrupt counter
Interrupt counter operation requires more than the simple designation of a set
value.
To use the interrupt counter for control purposes, comparison instructions (=,
<=, etc.) must also be used to enable comparisons with the set value, with an
internal relay (M), etc., being switched ON or OFF according to the
comparison result.
Diagram 9.36 shows a sample program in which M0 is switched ON after 10
interrupt inputs are performed. (In this example, "C300" is the interrupt counter
No. corresponding to I0.)
(c) Setting the interrupt counter
In order to use interrupt counters, set Interrupt counter start No. at the "PLC
system" tab screen in the "(PLC) Parameter" dialog box.
The number of points indicated in Table9.6 starting from the set counter number is
used as interrupt counters.
In order to use an interrupt counter, an "interruption permitted" status must be
established by E1 instruction at the main routine program.
Diagram 9.36 Ladder example when interrupt counter is used for control
Table9.6 Number of interrupt counter points of each CPU module
Basic model QCPU
High Performance model QCPU,
Process CPU, Redundant CPU
128 points, starting from the set counter number, are
used as interrupt counters.
When the first interrupt counter No. is set to C300,
C300 to 427 are used as interrupt counters.
256 points, starting from the set counter number, are used as
interrupt counters.
When the first interrupt counter No. is set to C300, C300 to 555
are used as interrupt counters.
=
M0
K10 C300
I0
I1
I2
I127
C300
C301
C302
C427
Values corresponding to
the interrupt counter No.
Interrupt counter (128 points)
I0
I1
I2
I255
C300
C301
C302
C555
Interrupt counter (256 points)
Values corresponding to
the interrupt counter No.