Mitsubishi FX3U-?*MR/ES - Page 228

220
FX3U Series Programmable Controllers
User’s Manual - Hardware Edition
11 Use of High-speed Counters (C235 to C255)
11.9 Calculation of Response Frequency and Overall Frequency
1) Calculation of overall frequency
The overall frequency is calculated by the high-speed comparison instruction used in the program based
on the above table.
Overall frequency ≥ Sum of "response frequency of high-speed counter × Magnification for
calculation of overall frequency"
2) Example of calculation
When only HSZ instruction is used six times in a program, the frequency is calculated by the formulas
shown in the "Only HSZ instruction" column in the above table.
High-speed counter No. to be
used
Input
frequency
Calculation of max.
response frequency
Magnification
for
calculation of
overall
frequency
Instruction
to be used
C237
Operation as
software counter
20kHz 30 - 6(times) = 24kHz
×1
HSZ instruc-
tion is used
six times.
C241
Software counter
10kHz 30 - 6(times) = 24kHz
×1
C253(OP)
[4 edge count]
2kHz {30 - 6(times)} / 4 = 6kHz
×4
1) The overall frequency is calculated as shown below because HSZ instruction is used six times.
Overall frequency = 50 - 1.5
× 6 = 41kHz
2) The sum of the response frequencies of the high-speed counters used is
calculated as shown below.
"20kHz
× 1[C237]" + "10kHz × 1[C241]" + "2kHz × 4[C253(OP)]" = 38kHz ≤ 41kHz