Mitsubishi Electric MELSEC-L Series LD40PD01, User Manual

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9 CREATING A HARDWARE LOGIC
9.2 Multi Function Counter Block
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Linear counter mode
When the linear counter mode is selected, the count operation is performed between the lower limit value and the upper limit
value. The following table shows the setting ranges (lower limit value and upper limit value).
The linear counter mode can be set only for a 32-bit counter timer block.
If "Count Value" has reached the upper limit value in up count, "Count Value" does not change in the next up count and the
overflow error (error code: 100
 H) occurs. "Count Value" does not change until the preset function is performed even if down
count is performed.
If "Count Value" has reached the lower limit value in down count, "Count Value" does not change in the next down count and
the underflow error (error code: 101
 H) occurs. "Count Value" does not change until the preset function is performed even if
up count is performed.
Ex.
The following figure shows how the counting range and the count value change in a 32-bit signed counter timer block when
the preset function is performed with the following settings: the upper limit value is 2147483647, the lower limit value is -
2147483648, and "Preset Value" is 500.
Multi function counter block Setting range
32-bit unsigned 0 to 4294967295
32-bit signed -2147483648 to 2147483647
(1) If "Count Value" has reached the lower limit value, an underflow occurs when a subtraction pulse is counted.
(2) If "Count Value" has reached the upper limit value, an overflow occurs when an addition pulse is counted.
Counting up Counting down
0
Upper limit value
Lower limit value
Count value
-2147483648
500
2147483647 -2147483647 -2147483648 2147483646
2147483647
498 499 500 501 502
(1) (2)
Upper limit value
to to
Lower limit value
Upper limit value
Lower limit value
Counting range
Count value