Response Frequency Of High Speed Counters - Mitsubishi Electric MELSEC FX3U Programming Manual

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
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.
Counter type
C235, C236, C238,
1-phase
C239, C241
1-counting
C237, C240, C242,
input
C243, C244, C245
C246, C248(OP)
1-phase
2-counting
C247, C248,
input
C249,C250
C251, C253(OP)
2-phase
2-counting
C252, C253, C254,
input
C254(OP), C255
*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
<Counter No.>
C235(1-phase 1-counting)
C236(1-phase 1-counting)
C237(1-phase 1-counting)
C253(2-phase 2-counting)
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 No.>
C235(1-phase 1-counting)
C236(1-phase 1-counting)
128
Overall frequency determined by condition of used instruction
Response
When HSCS, HSCR or HSZ
frequency
instruction is not used
60kHz
10kHz
200 kHz
- (Number of positioned axes
60kHz
+ Number of pulse width/period
measurement inputs)
10kHz
x 40 kHz
30kHz
5kHz
<Contents of use>
50 kHz is input.
50 kHz is input.
10 kHz is input.
5 kHz is input.
≤
Total115kHz 120kHz(Overall frequency)
<Contents of use>
50 kHz is input.
50 kHz is input.
≤
Total100kHz 120kHz(Overall frequency)
4 Devices in Detail
4.8 High Speed Counter [C] (FX3G PLCs)
When HSCS, HSCR or HSZ instruction
is used
60 kHz
*1
- (Number of positioned axes
- (Number of pulse width/period
measurement inputs x 20 kHz)
*1
x 5 kHz)