Related Devices (To Specify Counting Direction) [32-Bit Counter]; Functions And Operation Examples - Mitsubishi Electric MELSEC FX3U Programming Manual

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
4.6.3

Related devices (to specify counting direction) [32-bit counter]

When an auxiliary relay for switching the counting direction is set to ON, the counter executes down-counting,
and when set to OFF, the counter executes up-counting.
Counter No.
C200
C201
C202
C203
C204
C205
C206
C207
C208
4.6.4

Functions and operation examples

1. General type and latched (battery backed) type 16-bit up counters
• The valid set range of 16-bit binary up counter is from K1 to K32767 (decimal constant).
K0 provides the same operation as K1, and the output contact turns on at the first counting.
• In general type counters, the counter value is cleared when the PLC turns off. In latch type counters,
however, the counter value just before power failure is stored (backed up by the battery); The counter
value in the subsequent operations can be added to the last counter value.
• Every time the coil C0 is driven by the counting input X011, the current value of the counter increases.
When a coil instruction is executed 10 times, the output contact turns on.
After that, the current value of the counter does not change even if the counting input X011 turns on after
that.
When the RST input X010 turns ON and then RST instruction is executed, the current value of the counter
is reset to "0" and the output contact returns.
X010
X011
C 0
• The counter set value can be set by a constant (K) as shown above, or indirectly specified by a data
register number. For example, when D10 is specified and the contents of D10 are "123", it is equivalent to
"K123".
• If data beyond the set value is written to the current value register by MOV instruction, etc., the OUT coil
turns ON and the current value register becomes the set value when the next counting input is received.
• For latched (battery backed) type counters, the current value, output contact operation and reset status are
backed up against power failure.
In FX /FX
3U 3UC
In FX PLCs, latched type counters are backed up by the EEPROM built into the PLC.
3G
104
Counting
direction
Counter No.
switching
relay
M8200 C209
M8201 C210
M8202 C211
M8203 C212
M8204 C213
M8205 C214
M8206 C215
M8207 C216
M8208 C217
RST C 0
C 0 K10
Set value (constant)
Y000
It can be specified
indirectly also.
PLCs, latched type counters are backed up by the battery built into the PLC.
→ For details on backup methods against power failure, refer to Section 2.6.
Counting
direction
Counter No.
switching
relay
M8209 C218
M8210 C219
M8211 C220
M8212 C221
M8213 C222
M8214 C223
M8215 C224
M8216 C225
M8217 C226
X010
X011
Current
value
3
2
1
0
Y000
4 Devices in Detail
Counting
direction
Counter No.
switching
relay
M8218 C227
M8219 C228
M8220 C229
M8221 C230
M8222 C231
M8223 C232
M8224 C233
M8225 C234
M8226
10
9
8
7
6
5
4
4.6 Counter [C]
Counting
direction
switching
relay
M8227
M8228
M8229
M8230
M8231
M8232
M8233
M8234