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Frequently Asked Questions

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Scientific

Cells that have been contaminated with foreign material generally read low of the actual conductivity. Your zero (in air) conductivity reading is generally unaffected.

The conductivity error due to fouling will generally be proportional to the conductivity value. Conductivity is corrected not as an offset but as a ratio (multiplicative) error compared to a reference.

Salinity is a derivative measurement of temperature, conductivity, and pressure, and should be corrected by adjusting the component measurements. Generally speaking, an error in the conductivity measurement will correlate to a directly proportional error in the salinity measurement.

 

 

Category: Scientific

Field Procedures & Deployment

Oftentimes one will see data in their cast that looks erroneous or out of spec, but reviewing the timeline of each cast and the events which transpired can explain these jumps. If you are starting your cast while your CTD is on deck then the time during which the unit is running in air can be spiky or erratic, but this should be solved after the unit has been fully submerged and the pump has activated. The pump on time setting controls how fast the system will turn on the pump after deployment, so filtering out your deckside data can be done by calculating the number of scans to exclude using your pump on time setting, samples to average setting, and native sampling rate of your CTD.

Bubbles in the flow line can also cause spikes in your data towards the start of your deployment if the system isn’t able to normalize at the surface. We typically recommend units stay near the surface for 2-5 minutes in order to allow air bubbles to escape.

Finally, for additional resources in troubleshooting and smoothing data outliers for your CTD data, refer to our documentation on Seabird University.

 

The primary maintenance procedures that are outlined in the manual are for the bio-wiper (shutter) installation, the internal battery replacement and the bulkhead connector inspection. The shutter replacement is not always necessary, but, having the copper shutter and face plate parts available to swap out as needed, is a good idea.

Otherwise, the optics face should be inspected for film/streaks. The wiper may not work effectively if the copper faceplate condition deteriorates and damages the rubber blade. Some environmental conditions can start to “pit” the face plate surface, shredding the wiper blade. Replacing the face plate should be done if the wiper blade is getting damaged by being dragged across it. Otherwise, cleaning the active optics sensor area usually only requires DI water and a lab wipe (i.e. Kimwipe). Superficial scrapes and scratches on the optics face are unlikely to significantly affect the measurement.

Working with the shutter, moving it for inspection and/or removing it to install a new one, requires the instrument to be powered ON… keeping power to the shutter motor and commanding the open/close positions via software command/control. When moving/removing the shutter, it should NOT BE MOVED MANUALLY! There are gears in the ECO shutter motor that can strip easily with the wrong manual motion, unpowered. The manual motion in the wrong direction and speed, can overcome some of the gear ratios at play when they are back-driven.

Terminal emulator programs (as opposed to ECO View) are the most direct platform for working with the ECO’s. However, their use depends on one’s preference for how to interface with the instruments.