2-Phase 2-Count Input - Mitsubishi Electric MELSEQ FX3S Series User Manual

FX Series Programmable Controllers
3S
User's Manual - Hardware Edition

10.5.3 2-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 C251
X011
X012
C251
M8251
A-phase
input
X000
Main unit
2) For C254
X011
RST
X012
C254
C254
Y004
M8254
Y005
B-phase
input
A-phase
input
X000 X001
Main unit
• A 2-phase encoder generates A-phase output and B-phase output between which there is a 90 phase
difference. The high-speed counter automatically counts up or down according to the output as shown
below.
A-phase
+1
B-phase
Up-counting
• The down-count/up-count operations of C251 to C255 can be monitored through the ON/OFF operations
of M8251 to M8255.
ON : Down-counting
OFF: Up-counting
• While X012 is on, C251 counts the operation of the input
RST C251
• While X011 is turned on, the counter is reset when RST
K1234
C251
• When the current value exceeds the setting, Y002 turns on, and
Y002
Y003
• Y003 turns on (down-count) or off (up-count) according to the
B-phase
input
X001
• C254 starts counting immediately when the input terminal X006
C254
• C254 is reset by X011 on the sequence, and it is reset
D0 (D1)
• When the current value exceeds the setting (D1, D0), Y004
The setting is (D1, D0)
• Y005 turns on (down-count) or off (up-count) according to the
External start
input
External reset
input
X002 X006
+1 -1 -1
Down-counting
terminals X000 (A-phase) and X001 (B-phase) through
interruption.
instruction is executed.
when the current value becomes lower than the setting, Y002
turns off.
counting direction.
is turned on while X012 is on. The count input terminals are
X000 (A-phase) and X001 (B-phase).
immediately when X002 is turned on.
operates, and when the current value becomes lower than the
setting, Y004 turns off.
counting direction.
10 Use of High-speed Counters
10.5 Handling of High-speed Counters
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