Mitsubishi FX2-16E series, User Manual

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214
FX
3U
Series Programmable Controllers
User’s Manual - Hardware Edition
11 Use of High-speed Counters (C235 to C255)
11.6 Handling of High-speed Counters
• When the current value increases from -6 to -5, the output contact is set, and when the value decreases
from -5 to -6, it is reset.
• The current value increases and decreases regardless of the operation of the output contact. However,
when the counter’s value increments from 2,147,483,647, it changes to -2,147,483,648. In the same
manner, when it decrements from -2,147,483,648, it changes to 2,147,483,647. (This type of counter is
called a ring counter.)
• When RST instruction is executed after the reset input X011 turns on, the current counter’s value resets to
0, and the output contact is restored.
• The current values, output contact operations and reset status of the high-speed counters for retention
upon power failure are kept even if power is turned off.
11.6.2 1-phase 2-count input
These counters are 32-bit up-count/down-count binary counters.
The operations of the output contact according to the current value are the same as those of the above-
mentioned 1-phase 1-count input high-speed counters.
Examples of program
1) For C246
• While X012 is on, C246 increments the value when the input
terminal X000 switches from OFF to ON and decrements the
value when the input terminal X001 switches from OFF to ON.
• The down-count/up-count operations of C246 to C250 can be
monitored through the ON/OFF operations of M8246 to M8250.
ON: Down-counting
OFF: Up-counting
2) For C249
• While X012 is on, C249 starts counting immediately when
the input terminal X006 turns on.
The up-counting input terminal is X000, and the down-
counting input terminal is X001.
• C249 can be reset on the sequence by X011.
For C249, X002 is allocated as reset input. When X002
turns on, C249 is immediately reset.
• The down-count/up-count operations of C246 to C250 can
be monitored through the ON/OFF operations of M8246 to
M8250.
ON: Down-counting
OFF: Up-counting
X000
Main unit
Up-counting
input
X001
Down-counting
input
The setting is (D3,D2)
X011
X012
C246
D2(D3)
RST C246
X011
X012
C249 K1234
RST C249
X000
Main unit
Up-counting
input
X001
Down-counting
input
X002 X006
External
reset input
External start
input