EXO Maintenance - NitraLED Sensor and Wiper Brush Installation

EXO Maintenance - NitraLED Sensor and Wiper Brush Installation

exo university cap

EXO Maintenance - NitraLED Sensor and Wiper Brush Installation

This video covers the installation of the NitraLED sensor, wiper brush, and alignment ring on the EXO sonde and setup using Kor Software.

Timestamps of specific moments of the video

  • 0:00 – Overview and required equipment
  • 1:00 – Safety Information
  • 1:15 – Preparing the Central Wiper
  • 1:50 – Sensor Installation
  • 2:42 – Wiper Position Information
  • 3:22 – Alignment Ring Installation
  • 3:58 – Wiper Brush Installation
  • 4:54 – Adjusting Settings in Kor

Video Transcript

In this video, we will install the EXO NitraLED sensor, the NitraLED wiper brush, and the alignment ring.

These items come together in the NitraLED Kit, which you can find on YSI.com. This kit should be used with an EXO2 or an EXO3 sonde that has a Central Wiper.

Let’s cover what you’ll need. As we discuss in the NitraLED calibration videos, the Turbidity sensor and Conductivity/Temperature sensor are required for accurate Nitrate values. Since we recommend having a Central Wiper, a Wiped Conductivity/Temperature sensor would work best. You will also need the NitraLED sensor, NitraLED brush, hex key, alignment ring, and the specialized o-rings provided in the NitraLED kit. You’ll also want to have o-ring grease, a 0.05-inch hex key, and the EXO sensor tool handy.

A quick safety tip: the NitraLED has UV-LEDs that emit UV light. Wear safety glasses and gloves to protect your skin and eyes, and avoid looking directly into the LEDs when the sensor is powered.

Starting with the Central Wiper, remove the wiper from the sonde, and remove the old o-rings and any zip ties. Take the new small orange o-ring and roll it up the Central Wiper until it sits under the brush guard. Remove the standard wiper brush using a 0.05-inch hex key. Now the Central Wiper is ready to install into the sonde. Next, we will install the sensors. In the EXO2 and EXO3, the NitraLED must be installed in the last port in the bulkhead for the proper function of the wiper brush: that is, Port 6 for EXO2 and Port 4 for EXO3.

Apply a small amount of o-ring grease to lubricate the connectors. Just enough to make the connectors shiny but not too much to leave a visible residue. Install the Central Wiper in the center port, followed by the other sensors, making sure you have a Turbidity sensor and Conductivity/Temperature sensor installed in two of the ports.

Since the new wiper brush has an extra arm for specialized cleaning of the NitraLED sensing window, that arm will park over Port 5, and potentially interfere with Conductivity, and some optical-based sensor measurements, such as Turbidity. To avoid this, make sure that in Port 5 of your EXO2, next to your NitraLED in Port 6, you have installed a sensor that will not experience optical interference. pH, an Ion Selective Electrode, or Dissolved Oxygen are all sensors that are not affected by the wiper. This is not an issue for the EXO3 since there is no port under the brush arm.

Next, we will install the alignment ring. Line up the square-shaped cutout of the ring over the wiper brush guard. Slide the alignment ring onto the sensors, and seat it about a quarter inch below the top of the optical sensor faces. Or right over the brush guard seam. Then stretch the large o-ring over the alignment ring and into the groove. This will hold the alignment ring onto the sensors.

Now, slide the new wiper brush onto the wiper shaft, lining up the D-shaped notch. Before tightening the brush, gently rotate the wiper until the brush arm is seated in the NitraLED sensing window. This ensures the brush is installed in the optimal vertical position on the wiper shaft to allow the brush arm to pass through the sensing window with minimal resistance. The brush may not be seated all the way down the wiper shaft. Now tighten the set screw.

Gently rotate the wiper brush until the main sensor brush is seated in the brush guard and the brush arm is hovering over Port 5.

Now that we have our sensors, alignment ring, and wiper brush installed, we will connect to Kor to adjust the settings.

In Kor, select File, then Settings. The sonde will automatically recognize the NitraLED sensor, but we will double-check that the NitraLED output is set to On under the NitraLED tab. Under the Wiper tab, check that the wiper position is enabled. Then Save.

Navigate to Calibration. Select the Wiper to calibrate. Switch the mode to NitraLED mode. You will notice the wiper graphic changes. Click Apply.

In Live data, we will check that the wiper is functioning properly. The wiper will rotate through the sensors, stop, then rotate in the opposite direction. This allows the brush arm to clean the NitraLED sensing window and prevents the standard sensor brush from running into the longer NitraLED sensor. Small movements while the wiper reseats in the brush guard are normal. If adjustments are needed to realign the wiper brush in the home position, this can be done in the Wiper Calibration menu. You can select Jog Left or Jog Right to center the wiper brush. Once you have it centered, click Apply. We recommend running the wiper again to double-check the parking position.

Your NitraLED sensor, wiper brush, and alignment ring are now installed. Please check out our other EXO University videos, and thanks for watching!

Quick Links

Related Videos

Nitrate Sensor Calibration

Nitrate Sensor Calibration

Turbidity Calibration

Sonde Storage