Справочник Пользователя для Mitsubishi Electronics FX

FX Series Programmable Controllers

4-21

The counter shown in the example below, activates when its coil is driven, i.e. the C200 coil is
driven. On every occasion the input X14 is turned from OFF to ON the current value or current
count of C200 is incremented.

The output coil of C200 is set ON when the current value increases from “-6” to “-5”. However,
if the counters value decreases from “-5” to “-6” the counter coil will reset. The counters current
value increases or decreases independently of the output contact state (ON/OFF). Yet, if a
counter counts beyond +2,147,483,647 the current value will automatically change to
-2,147,483,648. Similarly, counting below -2,147,483,648 will result in the current value
changing to +2,147,483,647. This type of counting technique is typical for “ring counters”. The
current value of the active counter can be rest to "0" (zero) by forcibly resetting the counter
coil; in the example program by switching the input X13 ON which drives the RST instruction.
The counting direction is designated with special auxiliary relays M8200 to M8234.

•

Counters which are battery backed/ latched are able to retain their status information, 
even after the PLC has been powered down. This means on re-powering up, the latched 
counters can immediately resume from where they were at the time of the original PLC 
power down.

•

Please see the information table on page 4-19.

•

If  M8

 for C

 is turned ON, the counter will be a down counter. Conversely,

the counter is an up counter when M8

 is OFF.

FX

0(S)

FX

0N

FX FX

(2C)

FX

2N(C)

X13

X14

0

1

2

3

4

5

0

1

2

3

4

-6

-5

-4

-3

-2

-1

-7

-8

-6

-5

-4

-3

-7

0

Y1

X12

X14

K-5

X13

C200

RST

C200

X12

M8200

C200

Y1

If output is already
turned ON

Counters
present
value

Up counting

Down counting

Up counting