Chapter 2. SPECIFICATION S
2 - 15
2.6 Function Descriptions
The High-speed counting module can count high-speed pulse which cannot be proceed with the CPU
counting instructions (CTU,CTUD, etc.). Up to 24 bits binary (16,777,215) can be counted.
Pulse input mode is classified into 1-Phase (Phase A) pulse input and 2-Phase (Phase B) pulse input. In
1-Phase pulse input mode, there are two kinds of increment/decrement count methods. One is specified by
program and the other is specified by phase B pulse input signal. In 2-Phase pulse input mode, the
increment/decrement count method is specified by the phase difference between phase A and B pulsed.
2.6.1 Operation Modes
1) 1-phase Operation Mode (Increment /Decrement Count by Program)
When Phase A pulse input rises, the counter performs increment or decrement count by
decrement counter specification signal.
If the decrement counter specification signal is low the counter performs increment count, and if
high, it performs decrement count.
2) 1-phase Operation Mode (Increment /Decrement Count by Phase B Pulse Input)
When Phase A pulse input the counter performs increment or decrement count by Phase B pulse
input.
If Phase B pulse input is low, it performs decrement count, and if high, it performs increment count.
Phase A pulse
input
Decrement counter
specification signal
Counter
v a l u e
Increme
nt
Decrement
Incremen
t
Phase A pulse
input
Counter
v a l u e
Increme
nt
Decremen
t
Phase B
pulse input
Decrement