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

4.7.10 Response frequency of high speed counters

1. Response frequency of hardware counters
The table below shows the maximum response frequency of hardware counters.
When hardware counters are handled as software counters in some operating conditions, their maximum
response frequency becomes equivalent to that of software counters, and thus hardware counters are some
times subject to restrictions in total frequency.
Counter type
1-phase 1-counting input
1-phase 2-counting input
2-phase 2-count-
ing input
2. Response frequency and total frequency of software counters
The table below shows the maximum response frequency and total frequency of software counters.
When using the HSZ or HSCT instruction in a program, both the maximum response frequency and the total
frequency are limited for all software counters without regarding the operands of the instruction. When
examining a system or creating a program, consider the limitations, and use software counters within the
allowable range of maximum response frequency and total frequency.
1) When special analog adapters and FX
Following
software
Software counter with
Counter type
counter HSCS, HSCR,
HSZ or HSCT
instruction
C241,
C242, C235, C236,
C243, C237, C238,
1-phase
C244, C239, C240
1-counting input
C245
C244(OP),
−
C245(OP)
C247,
C248, C246,
1-phase
2-counting input C249, C248(OP)
C250
1 edge
2-
C252,
count
phase
C253(OP),
2-
C251, C253
count- C254,
4 edge
ing
count
C255
input
*1. When an index register is added to a counter number specified by a HSCS, HSCR, HSZ or HSCT
instruction, all hardware counters are switched to software counters.
*2. The high speed counters C244 (OP) and C245 (OP) can count up to 10 kHz.
→ For the conditions in which hardware counters are handled as software counters,
C235, C236, C237, C238, C239, C240
C244(OP), C245(OP)
C246, C248(OP)
1 edge count
C251, C253
4 edge count
→ For the conditions handled as software counters, refer to the previous page.
/FX
3U
When HSZ and HSCT
Magnifica-
instructions are not
tion for
used
calculating
total Maximum
frequency response
frequency
frequency
*1
(kHz)
×1
40
×1
10
×1
40
×1
40
×4
10
4.7 High Speed Counter [C] (FX3U/FX3UC PLC)
Counter No.
Series special function blocks/units are not used
3UC
Response frequency and total frequency according to instructions used
When only HSCT
instruction is used
Maximum Maximum
Total Total
response response
frequency
frequency frequency
(kHz) (kHz)
(kHz)
30
40 - (Num-
10
instruc-
80 60
30
30
(40-Num-
7.5
instruc-
tion) ÷ 4
4 Devices in Detail
refer to the previous page.
Maximum response frequency
Main unit FX -4HSX-ADP
3U
100 kHz
10 kHz 200 kHz
100 kHz
50 kHz 100 kHz
50 kHz 100 kHz
When only HSZ When both HSZ and HSCT
instruction is used instructions are used
Maximum
Total
response
frequency
frequency
(kHz)
(kHz) (kHz)
30-(Number
ber of
of instruc-
80−
*2
tion)
1.5×(Num
*2
tion)
ber of
instruc-
tion)
(30-Number
ber of
of instruction)
÷ 4
1
2
3
4
5
6
Total
frequency
(kHz)
7
60−
1.5×(Num
ber of
instruc-
tion)
8
9
10
119