Mitsubishi FX3UC SERIES User Manual page 157

FX Series Programmable Controllers
3UC
User's Manual - Hardware Edition
5.5 High-speed Counters (C235 to C255)
5.5.1 High-speed counter type and device number
1. High speed counter type
The main unit has built-in 32-bit high speed bi-directional counters (1-phase 1-count input, 1-phase 2-count
input and 2-phase 2-count input). These high-speed counters are classified into hardware counters and
software counters according to counting method.
For some high-speed counters, external reset input terminals or external start input terminals (start of
counting) can be selected.
2. Classification according to counting method
• Hardware counters: Counting by hardware.
• Software counters: Counting through interrupt handling by CPU
3. High speed counter type and input signal form
The types and input signals (waveforms) of high-speed counters (1-phase 1-count input, 1-phase 2-count
input and 2-phase 2-count input) are shown below.
Type of counter
1-phase 1-count
input
1-phase 2-count
input
1 edge
count
2-phase
2-count
input
4 edge
count
4. Cautions in connecting mating device
High speed counter inputs use general-purpose input terminals X000 to X007. Open collector transistor (24V
DC) output type equipment can be connected, but equipment having the output type shown below cannot be
connected.
Absolute encoders cannot be connected to high-speed counter inputs because the signal type is different.
→ For wiring, refer to "Section 7.2 Rotary Encoder [High-speed Counters C235 to C255]".
Output type disabling direct
connection
May be switched to software counters depending on the operating condition.
→ For the conditions under which they are handled as software counter,
Each counter must be used within specific limitations on maximum response
frequency and overall frequency.
→ For the restriction in response frequency by the overall frequency,
Input signal form
UP/
DOWN
+1 +1
UP
-1
DOWN
Phase A
+1 +1
Phase B
Up-counting
+1 +1 +1 +1 +1
Phase A
Phase B
+1 +1 +1 +1
Up-counting
Voltage output type
Line driver output type
Open collector output type that does not support 24V DC
5 Input Specifications and External wiring
5.5 High-speed Counters (C235 to C255)
Down-count or up-count is specified by turning on
or off M8235 to M8245.
ON: Down-counting
OFF: Up-counting
Up-count or down-count
The counting direction can be checked with
M8246 to M8250.
-1
ON: Down-counting
OFF: Up-counting
-1 -1
Automatic up-count or down-count according to
Down-counting
change in input status of phase A/B
The counting direction can be checked with
M8251 to M8255.
-1 -1 -1 -1 -1
ON: Down-counting
OFF: Up-counting
-1 -1 -1 -1
Down-counting
→ For programming, refer to programming manual.
refer to Subsection 5.5.8.
refer to Subsection 5.5.9.
Counting direction
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