Campbell CR800 Series, Operator'S Manual

Page: 376 / 598

Section 8. Operation
376
P Terminals
An internal 100 k Ω pull-up resistor pulls an input to 5 Vdc with the switch open,
whereas a switch closure to ground pulls the input to 0 V. An internal hardware
debounce filter has a 3.3 ms time-constant. Connection configurations are
illustrated in table
.
• Maximum input frequency = 90 Hz
CRBasic instruction: PulseCount()
An internal 100 k
Ω
pull-up resistor pulls an input to 5 Vdc with the switch open,
whereas a switch closure to ground pulls the input to 0 V. An internal hardware
debounce filter has a 3.3 ms time-constant. Connection configurations are
illustrated in table
.
•
Maximum input frequency = 90 Hz
• CRBasic instruction:
PulseCount()
C Terminals
Switch closure mode is a special case edge-count function that measures dry-
contact-switch closures or open collectors. The operating system filters bounces.
Connection configurations are illustrated in table
Switch Closures and Open
Collectors
(p. 378).
• Maximum input frequency = 150 Hz
•
CRBasic instruction: PulseCount()
8.1.3.5 Edge Timing
Edge time and period can be measured on
P
or
C
terminals. Applications for edge
timing include:
•
Measurements for feedback control using pulse-width or pulse-duration
modulation (PWM/PDM).
Measurements include time between edges expressed as frequency (Hz) or period
(µs).
C Terminals
•
Maximum input frequency <1 kHz
• CRBasic instruction:
TimerIO()
• Rising or falling edges of a square-wave signal are detected:
o Rising edge — transition from <1.5 Vdc to >3.5 Vdc.