thresholds required by the pulse count circuitry. See
Pulse measurement specifications
(p. 221) for
more information. The listed pulse measurement specifications account for attenuation due to
input filtering.
6.5.6.2 Pulse count resolution
Longer scan intervals result in better resolution.
PulseCount()
resolution is 1 pulse per scan.
On a 1 second scan, the resolution is 1 pulse per second. The resolution on a 10 second scan
interval is 1 pulse per 10 seconds, which is 0.1 pulses per second. The resolution on a 100
millisecond interval is 10 pulses per second.
For example, if a flow sensor outputs 4.5 pulses per second and you use a 1 second scan, one
scan will have 4 pulses and the next 5 pulses. Scan to scan, the flow number will bounce back
and forth. If you did a 10 second scan (or saved a total to a 10 second table), you would get 45
pulses. The total is 45 pulses for every 10 seconds. An average will correctly show 4.5 pulses per
second. You wouldn't see the reading bounce on the longer time interval.
6.6 Vibrating wire measurements
The data logger can measure vibrating wire sensors either directly, or through vibrating-wire
interface modules. Vibrating wire sensors are the sensor of choice in many environmental and
industrial applications that need sensor stability over very long periods, such as years or even
decades. A thermistor included in most sensors can be measured to compensate for temperature
errors.
The following image provides some examples for connecting vibrating wire sensors to the CR6.
You can use the Short Cut software to create a program and display a wiring diagram for most
types of vibrating wire sensors. Access the vibrating wire measurement in Short Cut through the
Generic Measurements sensors folder. Short Cut also has measurements for specific sensor
models in the Geotechnical & Structural and Water > Level & Flow folders.
6. Measurements
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