Basic Hardware and Function
277
8. Special I/O Functions
8.3.3
Quadrature bi-pulse counter
Function
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. Both rising and falling edges of each phase are counted.
Consequently, 4 times count value against the pulse frequency is obtained.
Phase A
Phase B
Up count
Down count
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 -2147483648 to 2147483647 (32-bit data).
Hardware condition
Phase A and phase B (X000 and X001)
ON/OFF pulse width: 100
m
s or more (max. 5 kHz)
Reset input (X002)
ON/OFF duration:
2 ms or more
Related registers
SW16: Function selection. Refer to section 8.1.
Function
Register/device
Remarks
Phase A
X000
Phase B
X001
Reset input
X002
Comparison value 1
SW19
×
SW18
Data range: -2147483648 to 2147483647
Comparison value 2
SW21
×
SW20
Count value
SW23
×
SW22
Soft-gate
S240
Operation is enabled when ON
Interrupt enable 1
S241
Interrupt 1 is enabled when ON
Count preset 1
S243
Used to preset the count value
Interrupt enable 2
S249
Interrupt 2 is enabled when ON
Count preset 2
S24B
Used to preset the count value
CTi Automation - Phone: 800.894.0412 - Fax: 208.368.0415 - Web: www.ctiautomation.net - Email: [email protected]