103
FX
3G
/FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
4 Devices in Detail
4.6 Counter [C]
1
Int
roduct
ion
2
O
ver
view
3
In
str
uc
tion
Li
st
4
D
evices
in D
etail
5
Spec
ified t
he
D
evice &
C
onst
ant
6
Bef
ore
Pr
ogr
am
m
ing
7
B
asic
In
st
ru
ct
io
n
8
FN
C
00-FN
C
09
P
rogr
am
F
low
9
FN
C
10
-FN
C
19
Mo
ve
&
Co
mp
are
10
FNC2
0-F
NC2
9
Ar
ith.
&
Logic
O
per
ation
4.6
Counter [C]
4.6.1
Numbers of counters
The table below shows counter (C) numbers. (Numbers are assigned in decimal.)
→
For high speed counters, refer to Section 4.7.
1. FX
3U
/FX
3UC
PLC
2. FX
3G
PLCs
*1.
This area is not latched (battery backed). It can be changed to a latched (battery backed) area by
setting the parameters.
*2.
This area is latched (battery backed). It can be changed to a non-latched (non-battery-backed) area
by setting the parameters.
Counter numbers not used as counters can be converted as data registers for storing numeric values.
4.6.2
Features of counters
The table below shows the features of 16-bit counters and 32-bit counters. They can be used in accordance
with the operating condition such as the counting direction switching and counting range, etc.
16-bit up counter
Counting range: 0 to 32767
32-bit bi-directional counter
Counting range:
−
2,147,483,648 to +2,147,483,647
General type
Latched (battery backed)
type (protected by battery
against power failure)
General type
Latched (battery backed)
type (protected by battery
against power failure)
C0 to C99
100 points
*1
C100 to C199
100 points
*2
C200 to C219
20 points
*1
C220 to C234
15 points
*2
16-bit up counter
Counting range: 0 to 32767
32-bit bi-directional counter
Counting range:
−
2,147,483,648 to +2,147,483,647
General type
Latched (EEPROM keep) type
General type
Latched (EEPROM keep) type
C0 to C15
16 points
C16 to C199
184 points
C200 to C219
20 points
C220 to C234
15 points
Item
16-bit counter
32-bit counter
Counting direction
Up-counting
Up-counting and down-counting can be switched
(as shown in Subsection 4.6.3)
Set value
1 to 32767
−
2,147,483,648 to +2,147,483,647
Set value specification
Constant (K) or data register
Constant (K) or a pair of data registers
Current value change
Does not change after counting up
Changes even after counting up (ring counter)
Output contact
Latches after counting up
Latches (in up-counting), or reset (in down-
counting)
Reset operation
When RST instruction is executed, current value of counter is reset to "0" and output contact
returns
Current value register
16 bits
32 bits