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FX3G/FX3U/FX3UC Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
4 Devices in Detail
4.8 High Speed Counter [C] (FX3G PLCs)
4.8.7 Response frequency of high speed counters
1. Response frequency and overall frequency
When any of the following functions/instructions is used, the overall frequency is restricted without regard to the
operand of the instruction.
Consider this restriction when examining the system or creating programs, and observe the specified overall
frequency range.
• When two or more high speed counters are used
• When the HSCS, HSCR, HSZ, PLSY, PLSR, DSZR, TBL, ZRN, PLSV, DRVI or DRVA instruction is used
• When the pulse width/pulse period measurement function is used.
*1. Number of axes used in the following positioning instructions:
PLSY (FNC 57), PLSR (FNC 59), DSZR (FNC150), TBL (FNC152), ZRN (FNC156), PLSV (FNC157), DRVI
(FNC158), DRVA (FNC159)
2. Calculation of the total frequency
Obtain the overall frequency using the following expression:
Total frequency ≥ [(Sum of used frequency of 1-phase counters) + (Sum of used
frequency of 2-phase counters)]
3. Calculation example
Example1: When HSCS, HSCR or HSZ instruction is not used, and instructions related to positioning (DRVI instruction
[Y000] and DRVA instruction [Y001]) are used
Overall frequency: 200 kHz - (2 axes x 40 kHz) = 120 kHz
Example2: When HSCS, HSCR or HSZ instruction is not used, and instructions related to positioning (DRVI instruction
[Y000] are used, Number of pulse width/pulse period measurement inputs(X003)
Overall frequency: 200 kHz - [(1 axes + 1 input) x 40 kHz] = 120 kHz
Counter type
Response
frequency
Overall frequency determined by condition of used instruction
When HSCS, HSCR or HSZ
instruction is not used
When HSCS, HSCR or HSZ instruction is
used
1-phase
1-counting
input
C235, C236, C238,
C239, C241
60kHz
200 kHz
- (Number of positioned axes
*1
+ Number of pulse width/period
measurement inputs)
x 40 kHz
60 kHz
- (Number of positioned axes
*1
x 5 kHz)
- (Number of pulse width/period
measurement inputs x 20 kHz)
C237, C240, C242,
C243, C244, C245
10kHz
1-phase
2-counting
input
C246, C248(OP) 60kHz
C247, C248,
C249,C250
10kHz
2-phase
2-counting
input
C251, C253(OP) 30kHz
C252, C253, C254,
C254(OP), C255
5kHz
<Counter No.> <Contents of use>
C235(1-phase 1-counting) 50 kHz is input.
C236(1-phase 1-counting) 50 kHz is input.
C237(1-phase 1-counting) 10 kHz is input.
C253(2-phase 2-counting) 5 kHz is input.
Total115kHz
≤ 120kHz(Overall frequency)
<Counter No.> <Contents of use>
C235(1-phase 1-counting) 50 kHz is input.
C236(1-phase 1-counting) 50 kHz is input.
Total100kHz
≤ 120kHz(Overall frequency)