2-Phase 2-Count Input - Mitsubishi FX3U SERIES User Manual

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

11.6.3 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 B-phase input
X000
Main unit
2) For C254
X011
X012
C254
M8254
B-phase input
A-phase input
X000
• A 2-phase encoder generates A-phase output and B-phase output between which there is a 90
difference. The high-speed counter automatically counts up or down according to the output as shown
below.
- Operation by 1 edge count
Phase A
Phase B
- Operation by 4 edge count
Phase A
Phase B
• 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
192
• While X012 is on, C251 counts the operation of the input terminals
RST C251
K1234
C251
• When the current value exceeds the setting, Y002 turns on, and
Y002
• Y003 turns on (down-count) or off (up-count) according to the
Y003
X001
RST C254
D0(D1)
C254
The setting is (D1,D0).
Y004
Y005
External start input
External reset
input
X001 X002 X006
Main unit
+1 +1 -1
Up-counting Down-counting
-1 -1 -1 -1 -1
+1 +1 +1 +1 +1
+1 +1 +1 +1 -1 -1 -1 -1
Up-counting Down-counting
11 Use of High-speed Counters (C235 to C255)
X000 (A-phase) and X001 (B-phase) through interruption.
While X011 is turned on, the counter is reset when RST instruction
is executed.
when the current value becomes lower than the setting, Y002 turns
off.
counting direction.
• C254 starts counting immediately when the input terminal
X006 is turned on while X012 is on.
The count input terminals are X000 (A-phase) and X001 (B-
phase).
• C254 is reset by X011 on the sequence, and it is reset
immediately when X002 is turned on.
• When the current value exceeds the setting (D1,D0), Y004
operates, and when the current value becomes lower than
the setting, Y004 turns off.
• Y005 turns on (down-count) or off (up-count) according to
the counting direction.
-1
11.6 Handling of High-speed Counters
°
phase