Mitsubishi Electronics FX3G User Manual

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3G
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3UC
 Series
Programming Manual - Basic & Applied Instruction Edition
4 Devices in Detail
4.8 High-Speed Counter [C] (FX3U/FX3UC PLC)
2. 1-phase 2-count input
These counters are 32-bit binary bi-directional counters, and the operation of the output contact for the current value is
equivalent to that in 1-phase 1-count input type high-speed counters described above.
• While X012 is ON, C246 executes up-count when the input X000 
turns from OFF to ON, and executes down-count when the input 
X001 turns from OFF to ON.
• The up/down-count operation of C246 to C250 can be checked with 
M8246 to M8250.
ON status: Down-counting
OFF status: Up-counting 
• While X012 is ON, C249 immediately starts counting when the input 
X006 turns ON.
The up-count input is X000, and the down-count input is X001.
• A high-speed counter can be reset by X011 in a sequence as shown 
in the figure, but C249 is immediately reset without any program 
when X002 is closed. So a program with X011 is not necessary. 
• The up/down-count operation of C246 to C250 can be checked with 
M8246 to M8250.
ON status: Down-counting
OFF status: Up-counting
3. 2-phase 2-count input
These counters are 32-bit binary bi-directional counters, and the operation of the output contact for the current value is
equivalent to that in 1-phase high-speed counters described above.
• While X012 is ON, C251 counts the operation of the inputs X000 (A 
phase) and X001 (B phase) as interrupt.
When X011 turns ON a RST instruction is executed and C251 is 
reset.
• When the current value becomes equivalent to or larger than the set 
value, Y002 turns ON. When the current value becomes equivalent 
to or smaller than the set value, Y002 turns OFF.
• Y003 turns ON (for down-count) or OFF (for up-count) according to 
the counting direction.
• When X006 turns ON while X012 is ON, C254 immediately starts 
counting. Its counting inputs are X000 (A phase) and X001 (B 
phase).
• In addition to reset by X011 in a sequence, C254 is reset 
immediately when X002 turns ON.
• When the current value becomes equivalent to or larger than the set 
value (D1, D0), Y004 turns ON. When the current value becomes 
equivalent to or smaller than the set value, Y004 turns OFF.
• Y005 turns ON (for down-count) or OFF (for up-count) according to 
the counting direction.
X011
X012
C249
K1234
RST
C249
X011
X012
C246
D2(D3)
RST
C246
Set value is (D3,D2)
X011
X012
C254
D0(D1)
RST
C254
X011
X012
C251
K1234
RST
C251
C251
Y002
Y003
C254
Y004
Y005
M8254
M8251