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9. SELECTING AND EXECUTING THE COUNTER FUNCTION
9. SELECTING AND EXECUTING THE COUNTER FUNCTION
9.1 Selecting the Counter Function
Current value storage area
{Addresses RWrn+0 to 1
Current value storage area
{Addresses RWrn+0 to 1
Current value storage area
{Addresses RWrn+0 to 1
Select and execute one of the following four counter functions.
Execute the selected function by switching on the counter function selection start
command or by applying a voltage to the external F.START terminal.
1) Count disable function ....................... Refer to Section 9.2
Inputs the signal while the count enable command is ON to stop pulse counting.
ON
Signal
OFF
Pulse input
2) Latch counter function ....................... Refer to Section 9.3
Latches the present value of the counter at the input of the signal.
ON
Signal
OFF
20
(RWrn+8 to 9)}
3) Sampling counter function ................. Refer to Section 9.4
Counts pulses entered during a preset time (T) which begins with the input of the
signal.
ON
Siglnal
OFF
T
(RWrn+8 to 9)}
4) Periodic pulse counter function ......... Refer to Section 9.5
Stores the present and previous counter values at preset intervals (T) while the
signal is entered.
ON
Signal
OFF
T
100
0
(RWrn+8 to 9)}
100
50
T
T
T
T
T
80
40
0
9 - 1
MELSEC-A
Present value storage area
{Addresses RWrn+0 to 1 (RWrn+8 to 9)}
Latch count value storage area
{Addresses RWrn+2 to 3 (RWrn+A to B)}
50
20
Sampling count value storage area
{Addresses RWrn+2 to 3(RWrn+A to B)}
0
T
T
Periodic pulse count previous,
present value storage areas
{Addresses RWrn+2 to 3(RWrn+A to B)}
{Addresses RWrn+4 to 5(RWrn+C to D)}
100
40
0
0
0
100
80
40
0
0
T
T
T
T
100
T
Previous value
Present value
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