APOGEE SO-411 Soil Response Thermistor Oxygen Sensor Instruction Manual
- June 6, 2024
- APOGEE
Table of Contents
APOGEE OXYGEN
INTRODUCTION
Apogee Instruments SO-411 Soil Response Thermistor Reference Oxygen Sensor is
a gaseous oxygen sensor designed primarily for use in soil applications.
Apogee SO-411 sensors purchased from METER come preconfigured by METER to work
seamlessly with METER ZENTRA series data loggers. The information in this
document explains how to integrate Apogee SO-411 sensors into the ZENTRA
system and attach an auxiliary power supply for the internal heaters. Details
of how the ZENTRA system handles the data are also included. Please read this
document carefully in its entirety before going out to the field. For more
information on Apogee oxygen sensors, please review the SO-411 User Manual
(apogeeinstruments.com/so- 411-sdi-12-soil-response-thermistor- reference-
oxygen-sensor).
INSTALLATION
Follow the steps listed in Table 1 to install Apogee oxygen sensors in the field.
Table 1 Installation
Tools Needed| Apogee SO-411 Oxygen Sensor (preconfigured by METER,
included in order)
Apogee AO-001 Diffusion Head (included in order)
Shovel or Auger (if the application requires sensor burial)
METER ZENTRA series data logger ZL6 or EM60
METER ZSC Bluetooth ®Sensor Interface (optional)
METER ZENTRA software ZENTRA Utility, ZENTRA Utility Mobile, or ZENTRA Cloud
---|---
Preparation| Conduct System Check
METER strongly recommends setting up and testing the system (sensors and
data loggers) in the lab or office.
Inspect and verify all components are intact.
Visit the data logger product page for the most up-to-date software and
firmware.
Verify all sensors are functional and read within expected ranges.
Install AO-001 Diffusion Head
Slide the included o-ring onto the male threads of the SO-411 sensor.
Screw the AO-001 diffusion head onto the SO-411 sensor.
NOTE: This is important to keep the Teflon ®filter from becoming plugged and
thereby
reducing oxygen diffusion to the sensing mechanism.
Calibrate Sensor for Atmospheric Pressure Dependence
To accurately measure oxygen concentration in relative units (%), Apogee
oxygen sensors must be calibrated in ambient air at the elevation that they
will be deployed (Section 2.2).
Installation| Install in Chosen Measurement Environment
For the most stable readings, sensors should be mounted vertically with the
opening pointed down and the cable pointed up.
For above-ground or enclosure installations, simply place the sensor in the
chosen measurement environment and secure as needed.
For buried installation, dig or auger a hole to the desired depth and install
the oxygen sensor. Carefully backfill the hole.
Secure and Protect Cables
NOTE: Improperly protected cables can lead to severed cables or disconnected
sensors.
Cabling issues can be caused by many factors such as rodent damage, driving
over sensor
cables, tripping over cables, not leaving enough cable slack during
installation or poor
sensor wiring connections.
Install cables in conduit or plastic cladding when near the ground to avoid
rodent damage.
Gather and secure cables between the sensors and the data logger to the
mounting post in one or more places to ensure cable weight does not pull the
plug free from its port.
Connect to Data Logger
Plug the sensor into a data logger.
Use the data logger to make sure the sensor is reading properly.
Verify these readings are within expected ranges.
For more instructions on connecting to data loggers, refer to Section 2.1.
Connect Heater Leads
Connect a continuous 12-VDC supply across the red (positive) and black
(negative) leads of the heater cable if the oxygen sensor is deployed in soil
(Section 2.3).
CONNECT TO METER ZENTRA SERIES LOGGER
Apogee SO-411 sensors are preconfigured by METER and work seamlessly with METER ZENTRA series data loggers. The sensors come with a 3.5-mm stereo plug connector (Figure 1) to facilitate easy connection with the data loggers. Apogee sensors come standard with a 5-m cable that splits into separate leads for the data logger and the heater power supply.
USING APOGEE OXYGEN SENSORS WITH ZENTRA SYSTEM
Check the METER download webpage for the most recent data logger firmware.
Logger configuration may be done using either ZENTRA Utility (desktop and
mobile application) or ZENTRA Cloud (web-based application for cell-enabled
ZENTRA data loggers).
-
Plug the stereo plug connector into one of the sensor ports on the logger (Figure 2).
-
Connect to the data logger via ZENTRA Utility with a laptop and USB cable or ZENTRA Utility Mobile app with a mobile device supporting Bluetooth communication.
-
Use ZENTRA Utility to scan the ports and make sure the sensors were properly identified by the logger and are reading properly.
METER data loggers should automatically recognize the Apogee sensor. -
Use ZENTRA Utility to set the measurement interval.
-
Use ZENTRA Utility to configure communication settings for data transfer to ZENTRA Cloud.
Sensor data can be downloaded from METER data loggers using either ZENTRA Utility or ZENTRA Cloud. Refer to the logger user manual for more information.
SENSOR CALIBRATION
Before installing the oxygen sensor, it must be calibrated at ambient oxygen
concentration (20.95%) at the elevation of the measurement site. Galvanic cell
type oxygen sensors respond to the absolute oxygen concentration, which is
dependent on absolute (barometric) pressure and temperature in addition to the
oxygen concentration of air. Therefore, oxygen sensors are not calibrated at
the factory and must be calibrated by the user before first use. It is
recommended that Apogee oxygen sensors be recalibrated periodically to
maintain best accuracy. Refer to the SO-411 user manual
(apogeeinstruments.com/so-411-sdi-12-soil- response-thermistor-reference-
oxygen-sensor).
Apogee sensors can be calibrated with a METER ZSC Bluetooth device or ZL6 data
logger.
CALIBRATION WITH ZSC AND ZENTRA UTILITY MOBILE
- Connect the Apogee oxygen cable to the ZSC device sensor port.
- Open ZENTRA Utility Mobile on an iOS or Android device.
- Connect to the ZSC device.
- Check that SO-411 data is communicating correctly with the ZSC (an inaccurate oxygen concentration and a temperature should appear).
- Go to More…
- Go to Device & Sensor Tools.
- Select Apogee oxygen sensor calibration.
- Go back to the device screen and ensure that the oxygen concentration now reads very close to 20.95%.
If Apogee oxygen sensor calibration is not listed under Device & Sensor Tools, the calibration can be done using a terminal window.
- Connect the Apogee oxygen cable to the ZSC device sensor port.
- Open ZENTRA Utility Mobile on an iOS or Android device.
- Connect to the ZSC Bluetooth.
- Check that the SO-411 is communicating correctly with the ZSC (an inaccurate oxygen concentration and a temperature should appear).
- Go to More…
- Go to Terminal.
- In the Send a Command box, type sliced?CHAMBER!
- Select Send.
- Go back to the device screen and ensure that the oxygen concentration now reads very close to 20.95%.
CALIBRATION WITH ZL6 AND ZENTRA UTILITY
- Connect the Apogee oxygen to an available port on the ZL6.
- Open ZENTRA Utility on a computer.
- Plug the micro-USB to the ZL6 and the USB to the computer.
- Click the Connect button on ZENTRA Utility to connect to the ZL6.
- Scan ports to check that the SO-411 is communicating correctly with the ZL6 (an inaccurate oxygen concentration and a temperature should appear).
- Go to Actions > Digital Sensor Terminal.
- Select the ZL6 port connected to the oxygen sensor cable.
- In the command box, type ?XAMBR!
- Select Send.
- Select Scan and ensure that the oxygen concentration now reads very close to 20.95%.
CALIBRATION WITH ZL6 AND ZENTRA UTILITY MOBILE
- Connect the Apogee oxygen sensor to an available port on the ZL6. Note the port as this will be used as [Y] for step 8.
- Press the TEST button on the ZL6 to advertise Bluetooth.
- Open ZENTRA Utility Mobile on an iOS or Android device.
- Connect to the ZL6 Bluetooth.
- Scan ports to check that the SO-411 is communicating correctly with the ZL6 (an inaccurate oxygen concentration and a temperature should appear).
- Go to More…
- Go to Device & Sensor Tools.
- Select the ZL6 port connected to the oxygen sensor cable.
- In the command box, type ?XAMBR!
- Select Send.
- Select Scan and ensure that the oxygen concentration now reads very close to 20.95%.
If Apogee oxygen sensor calibration is not listed under Device & Sensor Tools, the calibration can be done using a terminal window.
-
Connect the Apogee oxygen sensor to an available port on the ZL6. Note the port as this will be used as [Y] forfor step 8.
-
Press the TEST button on the ZL6 to advertise Bluetooth.
-
Open ZENTRA Utility Mobile on an iOS or Android device.
-
Connect to the ZL6 Bluetooth.
-
Check that the SO-411 is communicating correctly with the ZL6 (an inaccurate oxygen concentration and a temperature should appear).
-
Go to More…
-
Go to Terminal.
-
In the Send a Command box, type sdicmd [Y] ?XAMBR!, where [Y] is the port number that the oxygen sensor is plugged into.
For example, if the oxygen sensor is plugged into port 2, type sliced 2 ?XAMBR! -
Select Send.
-
Go back to the device screen and ensure that the oxygen concentration now reads very close to 20.95%.
HEATER POWER SUPPLY
Apogee oxygen sensors are equipped with an internal resistance heater. The
heater is designed to maintain the temperature of the sensing element at
approximately 2 °C above ambient temperature in condensing (100% relative
humidity) environments (e.g., soil). Heating the sensing element keeps
condensation from forming on the membrane, which would block the oxygen
diffusion path and result in artificially low oxygen measurements for an
extended period of time. To operate the heater, a continuous 12-VDC supply
should be attached to the heater leads.
Apogee oxygen sensors purchased from METER for use with METER ZENTRA series
data loggers come with a special cable addition that splits the sensor cable
into a stereo connector that connects to the data logger and a separate heater
cable. A continuous 12-VDC supply should be applied across the red (positive)
and black (negative) leads of this heater cable.
If mains power is available, the 12-VDC supply can be a simple “wall wart”. If
mains power is unavailable, a 12-V battery is appropriate and a solar panel
and charge controller can be used to maintain battery charge. Under most
conditions, a small battery (7 A · h) with a 5-W solar panel is sufficient to
heat multiple oxygen sensors. There are many battery, charge controller, and
solar panel options available online and from local retailers.
DATA INTERPRETATION
Apogee oxygen sensors used with the ZENTRA system report gaseous oxygen concentration in units of percent (%) and the internal sensor temperature in units that are configurable by the user.
TROUBLESHOOTING
This troubleshooting section details possible major problems and their
solutions. If the problem is not listed or these solutions do not solve the
issue, contact Customer Support.
Table 2 Troubleshooting
| Problem | Possible Solution |
|---|---|
| Sensor not responding | Check power to the sensor and logger. |
Check sensor cable and stereo plug connector integrity.
Check that the SDI-12 address of the sensor is 0 (factory default).
Check this with ZENTRA Utility by going to Actions, selecting Digital sensor
terminal, choosing the port that sensor is on, and sending the ?I! command to
the sensor from the dropdown menu.
Sensor values are not reasonable| Sensor has not been calibrated. See Section
2.2.
Condensation on the filter membrane is preventing oxygen diffusion to the
sensing element. See Section 2.3.
Cable or stereo plug
connector failure| If the stereo plug connector is damaged or needs to be
replaced, contact Customer Support for a replacement connector or splice kit.
If a cable is damaged refer to the METER wire-splicing guide for cable repair.
It is recommended that Apogee oxygen sensors be recalibrated periodically to maintain best accuracy. See Section 2.2 for directions on calibrating the sensor. Refer to the SO-411 User Manual (apogeeinstruments.com/so-411-sdi-12 -soil-response-thermistor-reference-oxygen- sensor)
CUSTOMER SUPPORT
NORTH AMERICA
Customer support representatives are available for questions, problems, or
feedback
Monday through Friday, 7:00 am to 5:00 pm Pacific time.
Email:
support.environment@metergroup.com
sales.environment@metergroup.com
Phone: +1.509.332.5600
Fax: +1.509.332.5158
Website: metergroup.com
EUROPE
Customer support representatives are available for questions, problems, or
feedback Monday through Friday, 8:00 to 17:00 Central European time.
Email: support.europe@metergroup.com
sales.europe@metergroup.com
Phone: +49 89 12 66 52 0
Fax: +49 89 12 66 52 20
Website: metergroup.de
C USTOMER SUPPORT
If contacting METER by email, please include the following information:
Name…………………….
Address…………………..
Phone…………………….
Email address…………
Instrument serial number…..
Description of the problem…
NOTE: For products purchased through a distributor, please contact the
distributor directly for assistance.
METER Group, Inc. USA
2365 NE Hopkins Court Pullman, WA 99163
T: +1.509.332.2756 F: +1.509.332.5158
E: info@metergroup.com W:
metergroup.com
METER Group AG
Mettlacher Straße 8, 81379 München
T: +49 89 1266520 F: +49 89 12665220
E: info.europe@metergroup.com W:
metergroup.de
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References
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