CQM1 1 and 2 the count of PLC high-speed counter mode

High speed counter counts 1 and 2 mode (circular or linear mode) specified in the DM6643 and DM6644, respectively.
1) ring-shaped pattern.
Ring mode, CTBL () set the maximum count value in +1. Increment the counter when the maximum count value to 0, when declining counters count from 0 to the maximum value, not negative.
Ring of points (maximum count value is +1) from the 1~65000.
2) linear model.
Counts in the range of -8388607~8388607 in linear mode, if beyond the scope of high speed counter count 1 or 2 allows, there will be an overflow or underflow, overflow counter PV stays in 08388607, underflow remained at F8388607, stop counting or comparisons, AR0509 (port 1) or AR0609 (port 2) to ON.
(Increment) pulse sequence: up along a rise b a b is falling edge falling edge;
Returns the (decreasing) pulse sequence: up rising edge b a b a falling edge is falling edge.