Selecting The Linear Counter - Mitsubishi Electric MELSECQ Series User Manual

5
FUNCTIONS
5.2.1
5
- 4
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Selecting the linear counter

(1) Linear counter operation
When the linear counter is selected, counting is operated in a range between -
2147483648 (lower limit value) and 2147483647 (upper limit value).
This can be used in combination with the preset function and the coincidence
detection function.
Present counter value
Subtraction
Overflow
Figure 5.1 Operation image of the linear counter
(2) Overflow error
(a) When the linear counter is selected for the counter format, if the present value A
(Un\G10 and 11)/present value B (Un\G200 and 201) falls below -2147483648
(lower limit value) in subtraction or exceeds 2147483647 (upper limit value) in
addition, an overflow error (error code: 100) will occur.
(b) If an overflow error occurs, 1 is stored in the overflow detection flag (Un\G12) and
the overflow error (error code: 100) is stored in the error code (Un\G20) in the
buffer memory, and counting is stopped. Even if a pulse is input in that condition,
the present value does not change from -2147483648 or 2147483647.
(c) An overflow error is cancelled by the preset function.
Executing preset stores 0 in the overflow detection flag (Un\G12) in the buffer
memory, allowing restart of counting. Note that, since data in the error code
(Un\G20) are retained until the error is reset, set 1 (ON) in the error reset
command (Un\G21) to reset the error.
(d) When system monitoring is performed during overflow error occurrence by
clicking [Diagnostics] - [System monitor] in GX Developer, a module error can be
identified.
5.2 Selecting Counter Format
5.2.1 Selecting the linear counter
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Overflow
+2147483647
0
Addition
-2147483648