Campbell CR3000 Micrologger, Руководство оператора

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Section 8. Operation
411
closure frequency is less than the maximum high-frequency measurement
frequency. Sensors that commonly output a switch closure or open-collector
signal include:
•
Tipping-bucket rain gages
•
Switch closure anemometers
•
Flow meters
Data output options include counts, frequency (Hz), and running average.
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 f
requency = 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. 413).
• 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).