Use Of High-Speed Counters; Outline; Types Of Counting And Operations; Types And Input Signal Forms - Mitsubishi Electric MELSEC-F FX3G Series User Manual

FX Series Programmable Controllers
3G
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.
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.
Counter type
1-phase 1-count
input
1-phase 2-count
input
Phase A
2-phase 2-count
input
Phase B

11.2.2 High-speed counter device notations

The input terminal assignments for FX
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.
Standard Device Numbers
C248
C253
C254

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.
Terminals for connecting
Input terminals of main unit
→ For the input specifications for X000 to X007 of the main unit, refer to Section 10.2.
Input signal form
UP/
DOWN
+1 +1
UP
-1 -1
DOWN
+1 +1
Up-counting Down-counting
3G
Switched Device Numbers
C248(OP)
C253(OP)
C254(OP)
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.
ON:Down-counting
OFF:Up-counting
Automatic up-count or down-count according to change in
input status of phase A/B
-1 -1
The counting direction can be checked with M8251 to M8255.
ON:Down-counting
OFF:Up-counting
PLC high-speed counters can be switched when used in
Output form that can be directly connected
Open collector transistor output form (applicable to 24V DC)
11 Use of High-speed Counters
11.1 Outline
Counting direction
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