Cyclops Submersible Sensor
998-2100 Rev. 2.9 Page 8
3. Measurements with the Cyclops
3.1 Introduction
The following information will describe how to:
oDetermine and set the appropriate gain
oCalibrate the Cyclops using standards with known concentrations
oMake measurements with the Cyclops
oUse the Solid Secondary Standard
Note: To make accurate and repeatable measurements it is important to
keep the sensor clean; see section 4.1 for information on cleaning your
sensor.
3.2 Setting the Gain
Gain setting refers to the sensitivity configuration of the sensor. There are three
gain settings; X1, X10 and X100. As the gain increases, the sensitivity
increases and the concentration range decreases.
3.2.1 Gain Determination Procedure
1) For in vivo applications, take a natural sample of water from a
sampling station where you plan to deploy the Cyclops. Applying
good measurement practices, store it properly and quickly transport it
to a laboratory where you have the Cyclops connected to a multi
meter and DC power source (see Figure 1).
2) Pour the water sample into a clean glass beaker and submerge the
optical end of the Cyclops (see Appendix B for “Recommended
Measurement Practices for using your Cyclops in the Lab” for how
best to accomplish these steps).
3) Activate the X10 gain setting (see Wiring Guide Appendix C) if you
believe the sample to represent a typical condition. You would like to
obtain a signal from the sample that is significantly higher than a
blank sample (de-ionized water or filtered seawater), but not a signal
that is close to the maximum of 5 Volts.
4) If the sample signal is high, (>3.0 V for example) you may choose to
use the X1 gain instead of the X10 gain setting so that you avoid
going over scale once you deploy the Cyclops.
5) If the sample signal is very low (<0.3V) you may choose to use the
X100 gain setting to achieve higher sensitivity but a smaller
measurable range
This process is easier for dye tracing applications. Simply create the dye
dilution of interest and record what signal level it provides on the three
gain settings.