Mitsubishi FX3UC SERIES User Manual page 168

FX Series Programmable Controllers
3UC
User's Manual - Hardware Edition
1) Calculation of overall frequency
The overall frequency is calculated using the above table according to the high-speed comparison
instructions being used in the program.
Overall frequency ≥ Sum of "response frequency of high-speed counter × Magnification for
calculation of overall frequency"
2) Example of calculation
When only the 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
C237
C241
C253 (OP)
[4 edge count]
1) The overall frequency is calculated as shown below since HSZ instruction is
used six times.
Overall frequency = 80 - 1.5 × 6 = 71kHz
2) The sum of the response frequencies of the high-speed counters being
used is calculated as follows:
"30kHz × 1[C237]" + "20kHz × 1[C241]" + "4kHz × 4[C253(OP)]" = 66kHz ≤ 71kHz
2. When FX /FX
3U
Examples of calculation are given in the heavy-line frame.
Software
counters
with
HSCS,
Counter
Counter type HSCR,
Nos.
HSZ or
HSCT
instruction
C235
C241
C236
C242
C237
C243
C238
1-phase
C244
1-count input
C239
C245
C240
C244(OP)
−
C245(OP)
C247
C248 C246
1-phase
2-count input
C249 C248(OP)
C250
1 edge C252
2-
count
C253
phase
C251
(OP)
2-
4 edge
C253
count
C254
count
input
C255
*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) cannot count signals of 10 kHz or more.
162
used frequency
Operation as
software counter
Software counter
Series special function blocks and analog special adapters are used
3UC
Magni-
ficatio
n for
Neither HSZ nor
calcu-
HSCT instruction
lation
Max.
of
response
overall
frequency
frequency
frequ-
(kHz)
ency
*1
×
1 30
×
10
1
×
1 30
×
1 30
×
7.5
4
Input Calculation of max.
response frequency
30kHz 40 - 6(times) = 34kHz
20kHz 40 - 6(times) = 34kHz
{40 - 6(times)} / 4 = 8.5kHz
4kHz
Response frequency and overall frequency depending on
instructions being used
Only HSCT
instruction
Max.
Overall Overall
response
frequency
frequency
(kHz) (kHz)
(kHz)
25
10
60 50
25
25
6.2
5 Input Specifications and External wiring
5.5 High-speed Counters (C235 to C255)
Magnification
for
calculation of
overall
frequency
×
1
×
1
×
4
Both HSZ and HSCT
Only HSZ instruction
instructions
Max. Max.
Overall
response response
frequency
frequency frequency
(kHz)
(kHz) (kHz)
30 - 25 -
(number of (number of
instruc- instruc-
×
50 - 1.5
*2
tions) tions)
(number of
instruc-
tions)
(30 - (25 -
number of number of
instruc- instruc-
tions) / 4 tions) / 4
Instruction
to be used
HSZ instruc-
tion is used
six times.
Overall
frequency
(kHz)
×
50 - 1.5
*2
(number of
instruc-
tions)