86
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
4 Devices in Detail
4.6 Counter [C]
2. 32-bit counter
1) Specification by constant (K)
2) Indirect specification (D)
4.6.6
Response speed of counters
Counters execute counting by cyclic operating for contact operations of internal signals X, Y, M, S, C, etc.
inside the PLC.
For example, when X011 is specified as counting input, its ON duration and OFF duration should be longer
than the cycle time of the PLC (which is tens of Hz or less usually).
On the other hand, high speed counters described later execute counting as an interrupt processing for
specific input, and can execute counting at 5 k to 6 kHz without regard to the cycle time.
→
For high speed counters, refer to Section 4.7.
4.6.7
Handling counters as numeric devices
Counters use output contacts operating in accordance with the set value or use the counter value (current
value) as numeric data for control.
The figure below shows the structure of the current value register of a counter. When a counter number is
specified in an operand of an applied instruction in execution, the counter is handled as a device storing 16-bit
or 32-bit data in the same way as data register.
A 32-bit counter is handled as 32-bit data.
1. Structure of register storing current value of counter
1) 16-bit
2) 32-bit
X003
C200
K43,210
Constant (decimal constant):
−
2,147,483,648 to +2,147,483,647
43210 counts
X001
FNC 12
DMOV
K43210
D5(D6)
X003
C200
D5(D6)
Pairs of data registers are used for indirect specification.
Use a 32-bit instruction for writing the set value, and make
sure that the latter of paired registers (D6 in this example)
does not overlap in other programs because it's invisible in
ladder format.
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
2
4
8
16
32
64
128
256
512
1024
2048
4096
8192
16384
b15
Sign
0: Positive
number
1: Negative
number
*1
b0
High
order
Low
order
16 bits
Available numeric value range
16-bit counter: 0 to 32767
32-bit counter:
−
2,147,483,648 to
+2,147,483,647
*1. The sign is valid only when a counter is handled as a substitute for data register.
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
1
2
4
8
16
32
64
128
256
512
1024
2048
4096
8192
16384
b31
Sign
0: Positive
number
1: Negative
number
b0
High
order
Low
order
32 bits
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
32768
65536
131,
07
2
262,
14
4
524,
28
8
1,
048,
5
7
6
2,
097,
1
5
2
4,
194,
3
0
4
8,
388,
6
0
8
16,
777
,216
33,
554
,432
67,
108
,864
134,
21
7,
728
268,
43
5,
456
536,
87
0,
912
1,
073,
7
41,
824
