Mitsubishi Electric MELSEC-Q Structured Programming Manual page 91

FXCPU Structured Programming Manual
[Device & Common]
5) In FX /FX
2N 2NC
Counter type
software counter
Software combined with
counter DHSCS, DHSCR
instruction
1-phase
1-counting C237 to C245 C235, C236
input
1-phase
2-counting C247 to C250 C246
input
2-phase
2-counting C252 to C255 C251
input
When using two or more high speed counters or when combining a high speed counter and the SPD,
PLSY or PLSR instruction, make sure that the sum of the processing frequency does not exceed the total
frequency shown above.
Calculation example (When the DHSCS, DHSCR and DHSZ instructions are not used)
Used high speed counter No.
C235(1-phase)
C237(1-phase)
C253(2-phase)
PLSY(Y0)
PLSY(Y1)
Total frequency = 20 kHz
Sum of processing frequency = 3 kHz + 4 kHz + 7 kHz + 4 kHz = 18 kHz
Sum of processing frequency (18 kHz) ≤ Total frequency (20 kHz)
PLCs
When DHSCS, DHSCR
Following
Magnification
for calculating
total frequency
Maximum
or DHSCZ
response
frequency
×1
×1
×2
Input/output
frequency
Handled as hardware
counter
Software counter
Software counter
Pulse output instruction
Response frequency and total frequency according to instructions used
When only DHSCS and
and DHSCZ
DHSCR instructions are
instructions are not
used
Total Maximum
frequency response
(kHz) frequency (kHz)
(kHz)
10 10
10 20 10
C251:5
5
C252 to C255:4
Magnification for calculating
total frequency
(Not required to be added
60kHz because C235 is handled as
hardware counter)
×1
3kHz
×2
2kHz
7kHz -
4kHz -
2 Devices in Detail
2.7 High Speed Counter [C]
When only DHSCZ
instruction is used
used
Maximum
Total
response
frequency
frequency
(kHz)
(kHz)
5.5
11 5.5
4
Calculated value
(Not required to be added
because C235 is handled as
hardware counter)
3kHz
4kHz
7kHz
4kHz
1
2
Total
frequency
(kHz)
3
5.5
4
5
6
7
89