Ring Counter Function - Mitsubishi Electric RD62P2E Application User's Manual

Ring counter function

Operation of the ring counter
This function repeatedly counts pulses between the values stored in CH1 Ring counter lower limit value setting (Un\G20 to
Un\G21) and CH1 Ring counter upper limit value setting (Un\G22 to Un\G23). When the ring counter function is selected, an
overflow error does not occur. The preset function and coincidence output function can be used with this function.
Present counter value
Counting down
Count range of the ring counter
The count range is determined by the relationship between the ring counter lower limit value or ring counter upper limit value
and the value in CH1 Present value (Un\G2 to Un\G3) when CH1 Count enable command (Y4) is turned on or when the
preset function is performed. Normally, the count range is Ring counter lower limit value  Present value  Ring counter upper
limit value.
■When the count range is Ring counter lower limit value  Present value  Ring counter upper
limit value (normally used)
• When pulses are counted up, the ring counter lower limit value is automatically stored in CH1 Present value (Un\G2 to
Un\G3) when the present value reaches the ring counter upper limit value.
• When pulses are counted down, even when the present value reaches the ring counter lower limit value, the ring counter
lower limit value is held as the lower limit, and the value of Ring counter upper limit value - 1 is stored in CH1 Present value
(Un\G2 to Un\G3) at the next count-down pulse input.
Both when pulses are counted up and when pulses are counted down, the ring counter upper limit value is not stored in CH1
Present value (Un\G2 to Un\G3). For example, when the count enable command is valid while the ring counter lower limit
value is 0, the ring counter upper limit value is 2000, and the present value is 500, the count range and the present value will
change as follows.
-2147483648
Present value
500 501 to
1 FUNCTIONS
18
1.2 Selecting a Counter Type
+2147483647
CH1 Ring counter upper limit (Un\G22 to Un\G23)
0
Counting up
CH1 Ring counter lower limit (Un\G20 to Un\G21)
-2147483648
Ring counter Ring counter
lower limit value upper limit value
0
Present value
500
Counting range
Ring counter upper
limit value
(2000)
1998 1999 0 1
The ring counter upper limit value,
2000, is not stored in CH1 Present
value (Un\G2 to Un\G3).
2000
2147483647
Ring counter
lower limit value
2 to 498 499