Campbell Scientific OBS-3A Turbidity and Temperature Monitoring System - Manual (Page 34)

OBS-3A Turbidity and Temperature Monitoring System
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. When wave statistics are chosen, the rate must be selected in
the Wave Setup box.
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 the longer of
the wave record length or the 2048 / rate.
The product of the rate and the duration cannot exceed 2048. NOTE
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.
6.8.5 Scheduled Configuration
Scheduled Configuration is used to sample at specific times in hours and
minutes on a 24-hour clock.
Before setting the survey configuration, run a Barometric Correction from
the Options screen. Be sure to do this while the OBS-3A is at the surface.
Doing so when the instrument is submerged will result in large depth errors.
See Section 6.5, Water-Density and Barometric Corrections, for more details.
All of the parameters for a scheduled configuration are described below. After
setting the parameters, press the Start Scheduled Survey button to begin
logging data.
26