Mitsubishi Electronics FX3G User Manual
107
FX
3S
/FX
3G
/FX
3GC
/FX
3U
/FX
3UC
Series
Programming Manual - Basic & Applied Instruction Edition
4 Devices in Detail
4.7 High-Speed Counter [C] (FX3S/FX3G/FX3GC PLCs)
1
Introdu
ction
2
Ov
ervi
ew
ew
3
Instruction
Li
st
4
D
evices
in Det
ai
l
5
Specifi
ed the
De
vice
&
C
onst
ant
ant
6
Bef
ore
ore
Pr
og
ra
mmi
ng
ng
7
Bas
ic
ic
Instruction
8
FN
C00-FN
C00-FN
C0
9
Program Fl
ow
9
FNC
10-FN
C19
Mov
e & Com
e & Com
pare
10
FNC
20-FNC
29
Arith. & Lo
gi
c
Operati
on
4.7
High-Speed Counter [C] (FX
3S
/FX
3G
/FX
3GC
PLCs)
4.7.1
Types and device numbers of high-speed counters
1. Types of high-speed counters
The main unit has built-in 32-bit high-speed bi-directional counters (1-phase 1-count, 1-phase 2-count and 2-phase 2-
count). Some high-speed counters are capable of using an external reset input terminal and an external start input
terminal (for counting start).
count). Some high-speed counters are capable of using an external reset input terminal and an external start input
terminal (for counting start).
2. Classification of high-speed counters according to counting method
These types of counters execute counting as CPU interrupt processing.
Observe both the restriction in response frequency for each counter and the restriction in total frequency when using
high-speed counters.
Observe both the restriction in response frequency for each counter and the restriction in total frequency when using
high-speed counters.
→ For the limitation of response frequency depending on the total frequency, refer to Subsection 4.7.7.
3. Types of high-speed counters and input signal forms
The table below shows the types (1-phase 1-count, 1-phase 2-count and 2-phase 2-count) and input signals
(waveforms) of high-speed counters.
(waveforms) of high-speed counters.
4. Cautions on counterpart equipment connected to high-speed counter inputs
General-purpose inputs X000 to X007 are used for high-speed counter inputs. An encoder
*1
adopting the output
method shown in the table below can be connected depending on the connected terminal.
Encoders adopting the voltage output method and absolute encoders cannot be connected to high-speed counter
inputs.
Encoders adopting the voltage output method and absolute encoders cannot be connected to high-speed counter
inputs.
→ For the wiring, refer to the Hardware Edition of the main unit.
*1.
A rotary encoder adopting the output method shown above may not operate correctly depending on the
electrical compatibility. Check the specifications before connecting an encoder.
electrical compatibility. Check the specifications before connecting an encoder.
Input signal form
Counting direction
1-phase
1-count input
1-count input
Down-count or up-count is specified by
turning on or off M8235 to M8245.
ON: Down-counting
OFF: Up-counting
turning on or off M8235 to M8245.
ON: Down-counting
OFF: Up-counting
1-phase
2-count input
2-count input
A counter executes up-count or down-
count as shown on the left.
The counting direction can be checked
with M8246 to M8250.
ON: Down-counting
OFF: Up-counting
count as shown on the left.
The counting direction can be checked
with M8246 to M8250.
ON: Down-counting
OFF: Up-counting
2-phase
2-count input
2-count input
A counter automatically executes up-
count or down-count according to
changes in the input status of the A/B
phase as shown on the left.
The counting direction can be checked
with M8251 to M8255.
ON: Down-counting
OFF: Up-counting
count or down-count according to
changes in the input status of the A/B
phase as shown on the left.
The counting direction can be checked
with M8251 to M8255.
ON: Down-counting
OFF: Up-counting
Output method of encoder which can be directly connected to input
terminal in main unit
terminal in main unit
Open collector transistor output method compatible with 24V DC
UP/DOWN
UP
DOWN
+1
+1
+1
−1
−1
−1
B phase
A phase
+1
+1
Up-counting
A phase
B phase
−1
−1
Down-counting