Selecting The Ring Counter - Mitsubishi Electric MELSECQ Series User Manual

5
FUNCTIONS
5.2.2
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Selecting the ring counter

(1) Ring counter operation
When the ring counter is selected, counting is repeated within the range between the
ring counter lower limit value (Un\G0 and 1) and ring counter upper limit value (Un\G2
and 3), which are arbitrarily set in the buffer memory.
No overflow error will occur when the ring counter is selected.
This can be used in combination with the preset function and the coincidence
detection function.
Present counter value
Subtraction
Figure 5.2 Operation image of the ring counter
(2) Count range of the ring counter
The count range varies depending on the present value A (Un\G10 and 11)/present
value B (Un\G200 and 201), and the ring counter lower limit value (Un\G0 and 1) and
upper limit value (Un\G2 and 3) at the time point of any of the following:
• Count enable command (Y04) changes from OFF to ON.
• Preset is executed.
POINT
• Set appropriate ring counter lower limit value (Un\G0 and 1)/upper limit
value (Un\G2 and 3) so that the following condition is satisfied.
"Ring counter lower limit value
If the count enable command (Y04) is turned from OFF to ON with this
condition not satisfied, a ring counter upper/lower limit value setting error
(error code: 500) is stored in the error code (Un\G20), and counting does
not start.
• To start the counting after occurrence of the ring counter upper/lower limit
value setting error (error code: 500), set the ring counter lower limit value
(Un\G0 and 1)/upper limit value (Un\G2 and 3) so that the following
condition is satisfied, and turn the counter enable command (Y04) ON,
OFF and ON again.
Note that the OFF time must be 2ms or longer.
search engine
+2147483647
Ring counter upper limit value (Un\G2 and 3)
0
Addition
Ring counter lower limit value (Un\G0 and 1)
-2147483648
(Un\G0 and 1)
"Ring counter lower limit value
( )
Un\G0 and 1
5.2.2 Selecting the ring counter
Ring counter upper limit value"
(Un\G2 and 3)
Ring counter upper limit value
(
Un\G2 and 3
5.2 Selecting Counter Format
1
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