Campbell Scientific OBS-3A Turbidity and Temperature Monitoring System - Manual (Page 39)

OBS-3A Turbidity and Temperature Monitoring System
• Sensor Measurements
Select the check boxes next to the sensor measurements you wish to make.
For Depth and OBS (NTU) use the drop-down boxes next to Statistics to
select the desired statistics for the measurement.
• Units of Measure
Select the units for depth (Meters or Feet).
• Water Density
Specify the water temperature and salinity. The specified temperature and
salinity only affect the depth calculation. They do not influence
temperature or salinity measurements.
• Sample Settings
o Duration
This is the length of time in seconds that the OBS-3A is measuring its
sensors. The duration must always be less than the interval. The
minimum duration is five seconds and the maximum is 2048 / rate.
The product of the rate and the duration cannot exceed 2048. NOTE
o Rate
Rate is the frequency of sampling for the duration of measurements.
All sensors are sampled at the same rate, typically 2, 5, 10, or 25 times
per second (Hz). For example, a rate of 25 Hz for a 60-second
duration will produce a sample with 1500 measurements for each
sensor.
o Power
This indicates the percentage of time over the duration of a sample
that sensors are ON. Higher power levels mean larger samples, better
statistics, and shorter battery life. Lower levels spare the batteries but
result in more random noise in sample statistics.
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