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11 Use of High-speed Counters
11.1 Outline
160
FX3G Series Programmable Controllers
User's Manual - Hardware Edition
11. Use of High-speed Counters
11.1 Outline
High-speed counters use input terminals X000 to X007 of the main unit for inputs, and offer counting up to
60kHz (1 phase).
Input terminals not used for high-speed counters are available for general-purpose inputs.
→ For the input specifications for X000 to X007 of the main unit, refer to Section 10.2.
11.2 Types of Counting and Operations
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).
For some high-speed counters, external reset input terminals or external start input terminals (start of
counting) can be selected.
11.2.1 Types and input signal forms
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.
11.2.2 High-speed counter device notations
The input terminal assignments for FX3G PLC high-speed counters can be switched when used in
combination with a special auxiliary relay. This section classifies these high-speed counter devices under the
following notations. Note that an "(OP)" input cannot be programmed.
11.2.3 Cautions in connecting mating device
Encoders with the output forms in the following table can be connected to the input terminals. (The encoders
may not function correctly depending on electrical compatibility. Check the specifications in advance.)
Voltage output type encoders and absolute encoders cannot be connected to the high-speed counter input
terminals.
Counter type Input signal form Counting direction
1-phase 1-count
input
Down-count or up-count is specified by turning on or off
M8235 to M8245.
ON:Down-counting
OFF:Up-counting
1-phase 2-count
input
Up-count or down-count
The counting direction can be checked with M8246 to M8250.
ON:Down-counting
OFF:Up-counting
2-phase 2-count
input
Automatic up-count or down-count according to change in
input status of phase A/B
The counting direction can be checked with M8251 to M8255.
ON:Down-counting
OFF:Up-counting
Standard Device Numbers Switched Device Numbers
C248 C248(OP)
C253 C253(OP)
C254 C254(OP)
Terminals for connecting Output form that can be directly connected
Input terminals of main unit Open collector transistor output form (applicable to 24V DC)
UP/
DOWN
UP
DOWN
+1 +1
-1 -1
Phase A
Phase B
+1
+1
Up-counting
-1
-1
Down-counting