Chapter 6 Applied Instructions Note 4: The SR special registers under “Counting mode” are 1 time frequency input by default. Use 2 for the input value for double frequency and 4 for four times frequency. Four times frequency is only applicable to the A/B 2-phase input counter. If the input value is not 1, 2 or 4 in SR, this indicates that the PLC uses one times frequency. Note 5: All single-phase counters in the table count using one times frequency, and the rising-edge counting mode changes the input point from OFF to ON. Note 6: P (Pulse input) and D (Direction) counters can reverse direction. When SM is ON, the counting direction (up/down) is reversed.
For example, when the preset direction input is OFF, the counter counts up. When SM switches to ON, the counter changes to count down. 6_ 6-281