MANTA
Water Quality Multi-probe
Eureka Environmental Engineering
Optical Dissolved Oxygen Sensor Calibration
Overview:
The Manta Water Quality Multi-probe (Manta) can monitor multiple parameters
consecutively in the field. The various sensors are factory installed and come “ready to
use” however, calibration of the device to the local environmental conditions (barometric
pressure, altitude) is very important for accurate data collection. This document will
provide a quick overview of how to calibrate the Manta optical oxygen sensor using a
laptop computer. It does not cover software installation or Amphibian operations.
Optical Dissolved Oxygen
The optical dissolved oxygen sensor can be
calibrated either with 100% water saturated
air, or the recommended method with a zero
oxygen sodium sulfite based standard. The
advantage to the zero oxygen solution is that
peak signal output from the sensor is actually
at zero mg/l.
The sensor is very linear, and may require
less frequent calibration than Clark cell
dissolved oxygen sensor. Clean sensor before
calibration and follow the steps on the Manta
Manager or Amphibian software to calibrate.
Equipment Overview:
The equipment required for calibration
of the Manta through a PC is: 1) Manta
probe with cable, 2) calibration cup, 3)
USB cable, and 4) PC with Manta
Manager software and USB drivers
installed. The blue USB cable provided
is specifically designed for the Manta
and is not to be used for any other
device. The cable attaches to a USB
port on the computer and to the prong
end of the Manta cable. Power for the
Manta is provided via the USB cable so
it is recommended to have the laptop plugged into a power outlet. It is also
recommended to use the same USB port each time.
Procedure:
Clean the Optical Oxygen sensing surface (red material, 1cm diameter) with a nonabrasive warm soap solution and a soft cloth. Do not use any abrasive solutions,
acetone, kerosene, or industrial cleansers.
Connect the Manta to the computer. Wait 15 seconds after the green light on the Manta
begins blinking. Start the Manta Manager software. The software takes a few moments
to find the Manta (searches the last port used therefore it is recommended to use the
same port each time). When the Manta is found, the computer display shows a
continuous reading:
On the left side are buttons for options. Select [ Calibration].
The calibration screen will show up and display all sensors on the Manta, last calibration
data, and the settings. From this screen, the barometric pressure, internal clock, and
altitude can be adjusted.
Select one of the oxygen sensor calibration buttons.
Depending on which type of oxygen reading (mg/L or %Sat), the displays are slightly
different. Note: %Sat allows barometric pressure and calibration solution to be adjusted
(right display).
The optical sensor can be calibrated at both 0% saturation and 100% saturation and
performing both methods is recommended.
0% Saturation Method: replace the storage cup on the probe end with the calibration
cup and fill with sodium sulfide zero DO solution, enter ‘0’ on the calibration solution
box. Wait for temperature to balance and press ‘calibrate’ or ‘start’.
100% Saturation Method: Shake a jar of water vigorsly for 1 minute, let settle for 5 to
remove the air bubbles. Place shaken water into the calibration cup. Enter ‘100’ into
the calibration solution box. Press [Start] or [Calibrate] depending on procedure used.
This is all one needs to do to calibrate the Manta Optical Oxygen Sensor. Record of the
calibration can be viewed on the first entry screen on the Manta Manager program. To
disconnect the Manta, just unplug it from the computer (a USB reject may need to be
performed on the computer first).
Some information and pictures in this document were obtained from the Eureka Manta
Users Guide ©2006.
Eureka Environmental Engineering
2113 Wells Branch Parkway Suite 4400
Austin, TX 78728
Tel: 512-302-4333
Fax: 512-251-6842