Cautions On Use; Response Speed Of Counters; Counters Handled As Numeric Devices - Mitsubishi Electric MELSEC-Q Structured Programming Manual

FXCPU Structured Programming Manual
[Device & Common]
2. 32-bit counter
1) Direct specification using a constant (K)
X003
CC200
K43210
2) Indirect specification using a data register (D)
X001
X003
CC200
*1 Make sure data registers used for indirect specification are not used in other programs.
2.6.6

Cautions on use

For writing the symbolic information and changing the set values of timers and counters using a peripheral
equipment, it is recommended to create programs with the set values specified indirectly.
If the set values are specified directly, programs cannot be restored from the symbolic information after the
set values are changed.
2.6.7

Response speed of counters

Counters execute counting by cyclic operation for contact operations of signals X, Y, M, S, C, etc. inside the
PLC.
For example, when X011 is used for counting input, its ON duration and OFF duration should be longer than
the scan time of the PLC (which is several tens Hz or less usually).
On the other hand, high speed counters described later execute counting as an interrupt processing for
specific input, and can execute counting at several kHz without regard to the scan time.
2.6.8

Counters handled as numeric devices

Counters use output contacts which operate in accordance with the set value, or use the count value (current
value) as numeric data for control.
The figures below show the structure of current value registers of counters.
When a counter number is specified in an input variable of an instruction, the counter is handled as a device
which stores 16-bit or 32-bit data in the same way as data registers.
A 32-bit counter is handled as 32-bit data.
OUT_C_32
EN ENO
CCoil
CValue
Constant (decimal constant)-2,147,483,648 to +2,147,483,647
43210 counts
DMOV
EN ENO
K43210 s d
D5
OUT_C_32
EN ENO
CCoil
*1
D5
CValue
*1
→ For high speed counters, refer to Section 2.7.
2 Devices in Detail
2.6 Counter [C]
1
2
3
4
5
6
7
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