In this video, we'll be replacing the EXO Optical Dissolved Oxygen sensor cap using Kor Software. You can also use an EXO Handheld or the Kor Mobile app.
These caps typically last over 12 months, depending on use conditions, and are warranted for one year.
New caps are shipped in a humidified storage container and include a sheet of unique coefficients required for updating the sensor after installation. You’ll notice that the serial number on the cap matches the serial number on the sheet. Make sure to hold on to this, as we’ll need it later!
To start, I’ve uninstalled the DO sensor from my EXO Sonde. This is not required, although it may make the replacement a little easier. Let’s remove the old cap by rotating it counterclockwise. With the cap removed, pinch the old o-ring with your fingers and remove it as well. Inspect the threading and use a Kimwipe to remove any debris or old grease. Additionally, take a look at the optical window and make sure there is no moisture or smudges present on the lens. Use a Kimwipe to clean and dry if necessary. Now we’ll carefully install the new o-ring by stretching it over the threading. We’ll then apply a light coat of grease until it is shiny.
Next, we’ll install the new ODO cap. We’ll leave it inside its humidified container during the installation process. Be sure to check the inside of the new cap to make sure there are no water droplets. Install the new cap by threading it clockwise on the sensor. Finger tighten until the cap is fully seated. I’ll remove the humidified container and dry it around the cap. The O-ring should be compressed between the cap and the sensor. This looks good, but we’re not finished yet! Let’s install the sensor on the EXO Sonde and connect to Kor Software.
A quick note on sensor installation: Whether you are dealing with a brand-new sensor or a used sensor, it is vital to make sure the connector is properly lubricated. EXO Sondes and sensors utilize wet-mate connectors to ensure performance down to 250 meters depth. These connectors reduce the risk of pin corrosion from leakage, but they must be properly maintained. This maintenance involves periodic cleaning and lubrication. Any time a sensor is uninstalled, it should be inspected, cleaned, and relubricated prior to installation. I’ll clean the connector with a Kimwipe and apply a thin layer of Krytox grease. Do not use too much grease; the connector should just be shiny. With that, we’ll proceed with sensor installation and then connect the sonde to Kor Software.
Once connected, we’ll navigate to the Instruments & Sensors screen and select the DO sensor settings. Here we’ll enter the new cap coefficients. Remember that sheet that was included with your cap? Let’s refer to that to update the K numbers in Kor Software. Just a reminder, these coefficients are generated at the factory, are unique to each sensor cap, and should be uploaded to the sensor for maximum accuracy. Once we’ve finished entering the numbers, click Apply to save the settings and push the coefficients to the sensor.
The sensor should be stored in a humid air environment. If the cap dries out, you can rehydrate it by soaking it in tap water overnight. After the new cap is installed and the settings are updated, it is necessary to perform a calibration before use.
Be sure to check out our other EXO University videos, and thanks for watching!