Toshiba Programmable Logic Controller V200 - Manual (Page 100)

Page 92
5.5 Quadrature Bi-pulse Counter
This function counts up or down the quadrature bi-pulse (2-phase pulses whose phases are shifted 90° each other).
Counts up when phase A precedes, and counts down when phase B precedes.
1-edge count:
The current value increments or decrements at the rising or falling edge of the phase B input after the phase A input
has turned on.
2-edge Count:
The current value increments or decrements at the rising or falling edge of the phase B input after the phase A input
has turned on or off.
4-edge Count:
The current value increments or decrements at the rising or falling edges of the phase A and B inputs.
Both rising and falling edges of each phase are counted.
Consequently, 4 times count value against the pulse frequency is obtained.
When the count value reaches the comparison value 1 (or 2), the I/O interrupt program#1 (or #2) is activated (if the
interrupt enable flag for each is ON). This counter operation is enabled while the soft-gate is ON. The count value is
reset to 0 when the soft-gate is changed from ON to OFF. The count value is also reset to 0 when the reset input
comes ON. When the soft-gate is OFF, the count value can be changed by writing the data into the comparison
value 1 (or 2) register and setting the count preset flag 1 (or 2) to ON. The comparison value 1 and 2 can be changed
even when the soft-gate is ON. The count value range is 0 to 4294967295 (32-bit data).