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FX Series Programmable Controllers Devices in Detail 4
4-30
4.11.6 1 Phase Counters - Assigned Start and Reset (C241 to C245)
These counters have one countable input
and 1 reset input each. Counters C244 and
C245 also have a start input.
When the direction fla
g
M8245 is ON, C245
counts down. When it is OFF C245 will count
up.
When X14 is ON, C245 resets in the same
manner as normal internal 32bit counters, but
C245 can also be reset b
y
input X3. This is
assi
g
ned automaticall
y
when counter C245 is
used (see previous counter tables).
Counter C245 also has an external start contact, a
g
ain automaticall
y
assi
g
ned. This is actuall
y
input X7. Once a
g
ain this data can be found on the previous counter tables.
When X7 is ON, C245 starts countin
g
, conversel
y
when X7 is OFF C245 stops countin
g
. The
input X15 selects and reserves the assi
g
ned inputs for the selected counter, i.e. in this case
C245.
The reason wh
y
these counters use assi
g
ned start (X7) and reset (X3) inputs is because the
y
are not affected b
y
the c
y
cle (scan) time of the pro
g
ram. This means their operation is
immediate and direct.
In this example C245 actual counts the number of OFF to ON events of input X2.
Note: Because C245 is a 32bit counter, its settin
g
data, specified here b
y
a data re
g
ister also
has to be of a 32bit format. This means that data re
g
isters D1 and D0 are used as a pair to
provide the 32bit data format required.
Device specification:
• All of these counters are 32bit up/down rin
g
counters. Their countin
g
and contact
operations are the same as normal 32bit up/down counters described on pa
g
e 4-21.
When the counters current value reaches its maximum or settin
g
value, the counters
associated contacts are set and held when the counter is countin
g
upwards.
However, when the counter is countin
g
downwards the contacts are reset.
Setting range:
• -2,147,483,648 to +2,147,483,647
Direction setting:
• The countin
g
direction for 1 phase counters is dependent on their correspondin
g
fla
g
M8 ; where is the number of the correspondin
g
counter, (C241 to C245).
- When M8 is ON the counter counts down.
- When M8 is OFF the counter counts up.
X15
D0
C245RST
X13
X14
M8245
C245