Frequently Asked Questions
- ECRN-100 - ECRN-50 - SUPPORTING SENSORS How do I check the calibration and then recalibrate the ECRN-50 or ECRN-100 tipping bucket rain gauge? The tipping bucket rain gauges have small stops that can be adjusted such that the bucket tips after the appropriate volume of water was collected in the bucket. Calibrate ECRN-50 when wet because a little water remains in the cup. Volume-per-tip values can be found in the rain gauge quick start guides below:
- PAR - PYR - SUPPORTING SENSORS Can PAR be estimated from total shortwave radiation?
It is better to measure PAR and total shortwave radiation (PYR); however, PAR can be estimated from total shortwave radiation by using a physically based model.
- PAR - PYR - SUPPORTING SENSORS How do I know when my PYR or PAR needs to be recalibrated? Use the Apogee Clear Sky calculator. The primary use of this calculator is to determine the need for recalibration of radiation sensors. It is most accurate when used near solar noon in the summer months.
- PAR - PYR - SUPPORTING SENSORS How do I mount the leveling plate to the mounting bracket? You can find PAR/PYR installation instructions in the quick start guide and on page 9 of the manual. On the leveling plate, the outer screws (with threads in the plate) are for leveling, and the inner screws (no threads) are used to secure the leveling plate to the mounting bracket. First, securely install the mounting bracket to a post, considering the optimal position for collecting accurate solar radiation data. Orient the sensor cable as described in the quick start and manual.
- Screw in the inner screws part of the way, to secure it to the mounting bracket.
- Screw in the outer screws until the bubble level indicates the leveling plate is level.
- Screw in the inner screws to completely secure the leveled leveling plate to the mounting bracket.
- Remove the green cap after installation is complete.
- SRS - SUPPORTING SENSORS Can I check downward facing SRS output using a white panel test? Yes, you could check downward facing SRS response in the field on a sunny day using a white panel. Ideally, a Spectralon panel should be used. The SRS field stop calibration check should be done with the field stop sensors pointing down at an angle toward a white Teflon panel or Spectralon panel, so that the field of view is totally encompassed by the white panel. Then, with the hemispherical sensors pointing up to collect irradiance data at the same location and time (with no obstructions in the field of view), radiance values * pi (3.14) should be approximately equal to irradiance values.Radiance = Irradiance/piIrradiance = Radiance * pi
- SRS - SUPPORTING SENSORS What is the calibration equation of my SRS sensor? Because the response of the SRS is linear, the calibration is a simple multiplier that converts the raw readings to a calibrated value. There is an offset that is set to account for the noise readings that occur when the sensor is in complete darkness (dark offset). Both of these values are sensor specific and vary to some degree. A firmware update protects the calibration coefficients because they are stored in an area of the flash memory that is not touched during an update.
- SRS - SUPPORTING SENSORS Why does the NDVI or PRI calculation show no results if the sensor wavelength output is zero? Is the sensor bad?
The sensor is not bad in this case. The NDVI or PRI calculation returns no results when data are zero in the denominator.
- SRS - SUPPORTING SENSORS Can I use SRS at the plant level? Yes, you can use the SRS at the plant level for field application where there is natural sunlight. Make sure there are no shadows in the measurement area, or remove the data during shady or dark conditions. The problem with shady conditions is that the data are not reliable. You may need more sensor replications at the plant level if you see more variation.If you plan on using a non-natural light source, this could be a big unknown about the effects of light intensity over time (intensity and distance changing over time). You would need to control these variables or measure them. For this reason, we recommend that the SRS sensors be used in the field with natural sunlight (field instruments only).
- SRS - SUPPORTING SENSORS What are some applications for SRS NDVI sensors?
- Intercepted photosynthetically active radiation
- Leaf area index
- Phenological stages of plant development
- Biomass accumulation
- Ground-based monitoring of vegetation density
- Drought indication
- Altered precipitation studies for drought tolerance
- Canopy health/senescence
- Spring canopy green-up
- Ground truthing remotely sensed NDVI
- SRS - SUPPORTING SENSORS What are some applications for SRS PRI sensors?
- Relative photosynthetic performance
- Monitoring plant stress
- Estimating gross primary productivity of an ecosystem
- Spatially distributed estimates of carbon flux in conjunction with eddy covariance system
- Vegetation productivity
- Drought indication
- Monitoring plant stress
- Onset of spring photosynthesis in evergreens
- SRS - SUPPORTING SENSORS What is the area of measurement? It depends on the angle and the height the sensor is installed. Below is an example. The Apogee calculator is a good resource for determining the area of measurement. Use the 36 degree (18 degree half angle) sensor.Field of view:The field of view (FOV) is reported as the half-angle of the apex of the cone formed by the target surface (cone base) and the detector (cone apex), as shown below, where the target is defined as a circle from which 98% of the radiation detected by the radiometer is emitted.Sensor FOV, distance to target, and sensor mounting angle in relation to the target will determine target area. Different mounting geometries (distance and angle combinations) produce different target shapes and areas, as shown below.
- SRS - SUPPORTING SENSORS How do I calculate NDVI? Calculate NDVI as:NDVI = (ρNIR − ρred) / (ρNIR + ρred)where, ρred and ρNIR are percent reflectances in the red and near infrared (NIR). ρ at each waveband is calculated as radiance/irradiance at each waveband, where radiance is reflected radiation intensity in that waveband and irradiance is incoming radiation intensity in that waveband. Here is an example SRS NDVI calculator: [Download calculator]
- SRS - SUPPORTING SENSORS Do SRS sensors need to be recalibrated? We recommend that the SRS be recalibrated annually. The sensors should be cleaned more frequently than this if needed. Check the SRS manual for cleaning instructions. The recalibration cost is $70 per sensor. Unfortunately, there is not a way to check the calibration in the field. It requires a light source of a known intensity and a calibration standard.
- Soil Moisture Sensor - ECH2O 5TE - Volumetric Water Content - TEROS 12 - GENERAL - GS3 What will measuring electrical conductivity give you a metric of versus VWC?
EC can give you the solute concentration of the soil, but is trickier to interpret than VWC since the VWC can be a confounding variable.
- TEROS 21 - Water potential - Soil Moisture Sensor - TEROS 11 - Volumetric Water Content - TEROS 12 - GENERAL - GS3 - TEROS What are important considerations when thinking about measuring water content and water potential in peatlands (with organic soils)?
Variability of your substrate is a big one. There is a lot of variability in soils as well, but we have better mechanisms to capture and account for variability in mineral soils. Good substrate-to-sensor contact is critical and trickier to accomplish (good installation), but it is achievable. You will most likely require a custom calibration for water content.
- ATMOS 14 - SRS - IRT - ECT - PAR - PYR - ATMOS 22 - ATMOS 41 - PHYTOS 31 - ECRN-100 - ECRN-50 How do I assemble the anemometer mast?
The anemometer mast is suitable to mount METER’s above-ground sensors: ATMOS 41, ATMOS 22, ATMOS 14, PAR, PYR, IRT, SRS, PHYTOS 31, ECRN-100, ECRN-50, and ECT. Additional brackets may be required for some products.
Anemometer mast kit: 1 extendable mast (fiberglass), 1 guy ring, 1 guy rope (7.6 m nylon rope), 3 guy rope anchors, and 1 mast base with center peg and set screw.
Mast diameter: 4.5 cm
Mast adjustable length: 1.3 to 2.3 m
Tools to bring to the field: measuring tape, long metal screwdriver, mallet, wrench, level, scissors, optional shovel, and lighter.
Installation: Position the mast base in the desired installation location, avoiding large rocks. Install the center peg using a mallet. Insert the mast into the base so that the center peg is inside the mast tube. With the mast in the base, turn the set screw so it is hand-tight against the mast. Then, gently turn the set screw with a wrench. Do not over tighten or the fiberglass pole will break. Put the guy ring over the extendable mast. Cut the guy rope into thirds (approximately 2.5 m each) and burn the ends with a lighter to prevent fraying. Position the rope anchors equidistant apart to be about 1 meter away from the mast. Screw the anchors into the soil at the same angle as the guy rope using a long metal screwdriver as a make-shift turning handle. Attach the guy rope to the guy ring in 3 equidistant holes (show below) using knots. Then knot each guy rope in the corresponding anchor. Pull the rope very tight and ensure the mast is level and straight.
Once the mast is secure, move the adjustable lever up to release the extendable mast. Move the lever down to secure the mast to the correct height. Install instruments following the sensor quick start guides and manuals.
Limitations: Rocky soils, long-term monitoring sites, locations with high animal traffic. The SRS extension arm may be too heavy for the fiberglass mast.
- Em50G - EM50 - EM60 - EM60G What happens if my logger breaks ? I heard you are discontinuing the EM Series loggers, What happens if my logger breaks?Your Em Series logger (Em50, Em50G,EM60,EM60G) will be supported for three years (or until parts are no longer available).Please call 509-332-5600, or email email@example.com for questions or concerns.
- Em50G Is the Em50G logger available everywhere?
The Em50G data logger is available in the United States, Canada, Latin America, Europe, Middle East, and other global locations.
Please call the METER sales team to verify the coverage in your location.
- Em50G - EM50 EM50/Em50g: What cable do I need to connect the logger and my computer?
The EM50 and EM50G use a proprietary USB-to-stereo cable. If you have a damaged or missing cable, please contact METER for a replacement.
- GS1 - TEROS 12 - GS3 - TEROS What is the volume of influence comparison for the GS1, GS3, and TEROS 12?
See our volume of influence article for a comparison of all METER soil moisture sensors.
- Em50G - EM60G Can a third-party software program be used to pull data from METER data loggers? You cannot use a third party program to pull data directly from our loggers. The software we make is written to provide optimal communication.If you wish to assess your data remotely, we offer API access to pull data from our servers and directly into your third party software.
- Em50G - EM50 - EM60 - EM60G How should I position my logger? The logger should be vertical, with the cables coming out of the bottom of the logger.Choose a location and orientation that provides the solar panel with the maximum amount of sunlight. In the Northern Hemisphere, this will typically mean that the data logger will face south; in the Southern Hemisphere, this will typically mean the data logger will face north
- Em50G - EM50 - EM60 - EM60G Is autoconfiguration only for serial sensors, or does it include also 10HS and EC-5?
Only digital sensors are automatically configured. You can simply use the drop-down menu to pick analog sensors (such as the 10HS and the EC-5) when these are used.
- Em50G - ZENTRA Cloud - ZENTRA Will the Em50G be compatible with the ZENTRA platform at some point?
- Em50G - EM60G What is the difference between the EM50G and the EM60G?
EM50G EM60G 5 ports 6 ports 1 MB of storage (36,000 records) 8 MB of storage (80,000 records) Reports 6x a day Reports up to every hour Optional solar panel Standard solar panel No GPS Standard GPS Can NOT host-A-41 Can host A-41 Physical FW update required Automatic over the air FW update Ech20 Utility Zentra Utility DataTrac3 / Webviewer Zentra Cloud Quad-band UMTS 3G with 2G fallback
- Soil Moisture Sensor - ECH2O 5TE - GS3 Can your 5TE or GS3 tell me the soil salinity or the pore water EC?
Our sensors measure bulk EC, not soil salinity or pore water EC. Pore water EC can be derived from bulk EC using various models, including the Hillhorst model. This is described more in our application note about soil EC.
- ECRN-50 - SUPPORTING SENSORS What is the volume per tip for the ECRN-50? ECRN-50 volume per tip: 5.0 ml/tipRainfall per tip: 1 mm/tip
- ECRN-100 - SUPPORTING SENSORS What is the volume per tip for the ECRN-100? ECRN-100 volume per tip: 4.02 ml/tipRainfall per tip: 0.2 mm/tip
- ECRN-100 - SUPPORTING SENSORS What is the maximum flow rate for the ECRN-100?
- SUPPORTING SENSORS - CTD-10/HYDROS 21 Can the CTD-10 survive a winter?
Possibly. If the sensor is in water, it must not be allowed to experience temperature below freezing (0 ◦C or 32 ◦F). If water freezes in the CTD sensor pressure transducer cavity, then ice formation will ruin the pressure transducer.
- DataTrac 3 - Em50G - SUPPORTING SENSORS - EM50 How do I correct the date on a bad dataset in DataTrac 3?
If the batteries are removed from the EM50 logger series without being connected to a computer, the EM50 will record data with incorrect timestamps. Here’s how to correct the timestamps permanently in DataTrac 3:
- In the table view, select ALL of the incorrect dates.
- From the Setup menu, select Timeshift.
- Enter the new start date of the first date in the selected records.
- Press OK, and the data will be corrected with the new date.
- DataTrac 3 - Em50G - ENVIRONMENT Software - SUPPORTING SENSORS - EM50 How do I graph plant available water?
In older versions of DataTrac, Plant Available Water was a setting that could be accessed from the top toolbar. In DataTrac 3, Plant Available Water is treated as a growing tool. To graph plant available water for any of your sensors:
- Click on the logger in the device tree where you would like to graph Plant Available Water.
- Click Configure in the toolbar.
- Select Virtual Port under Sensors and Measurements
- In the Virtual Measurement Type drop-down menu, select Growing Tools
- Under Select Derived Product Type drop-down menu, select Plant Available Water
- In the Volumetric Water Content drop-down menu, select the sensor data where you would like to apply the Plant Available Water model.
- Click Create Virtual Measurement
- Select your Approximate Mineral Soil Type or select User Defined Values and manually enter your percent volumetric water content at field capacity and permanent wilting point. Plant Available Water for each soil type will be estimated using methodology from the following reference: “Soil Water Characteristic Estimates by Texture and Organic Matter for Hydrologic Solutions”, K. E. Saxton and W. J. Rawls. Published in the Soil Science Society of America Journal. 70:1569-1578 (2006)
- Click OK
Learn more about determining plant available water from field capacity and permanent wilting point
- DataTrac 3 - Em50G - ENVIRONMENT Software - SUPPORTING SENSORS - EM50 How do I subscribe to an Em50G?
- Click Setup > Create New > Em50G Subscription
- Enter the Device ID and Password of the Em50G that you would like to subscribe to into the window that appears.
- Use the default server.
- If you would like to see all of the data from this Em50G, select All Data Points from the Retrieve dropdown menu.
- Click Subscribe.
- DataTrac 3 - Em50G - ENVIRONMENT Software - SUPPORTING SENSORS - EM50 Adding sensor data from different loggers to my graph
DataTrac 3 has the ability to integrate external measurements or measurements from a different logger into the graph that you’re viewing. To use this tool:
- Click on the device in the device tree to whose graph you would like to add data.
- Select Configure from the toolbar at the top of the DataTrac 3 main screen.
- Under the Sensors and Measurements heading, select Virtual Port.
- From the dropdown menu labeled Select a Virtual Measurement Type, select External Measurement
- A drop-down menu will now be displayed, containing a list of all other data loggers and their respective measurements.
- Select the desired logger and measurement.
- Click the Create Virtual Measurement button, and then click OK at the bottom of the page.
- DataTrac 3 - Em50G - ENVIRONMENT Software - SUPPORTING SENSORS - EM50 How do I apply a custom water content calibration to my sensor data?
Factory calibration curves are provided for mineral soils, potting soils, perlite, and rockwool. Many of these factory calibrations have been verified by independent researchers and published in peer-reviewed journal articles. If a factory calibration is not available, or you would like better accuracy, you can provide a custom calibration to the soil moisture sensor data collected.
You can provide a custom calibration for each sensor independently. To use a custom calibration in DataTrac 3:
- Click the Configure button in the toolbar of DataTrac.
- Under Sensors and Measurements list, expand the port containing the sensor for which you would like to input a custom calibration.
- Click on Volumetric Water Content under that port.
- Select User Defined from the Approximate Soil Media drop-down menu.
- Enter the coefficients for your custom calibration in the spaces provided.
- SUPPORTING SENSORS - EM50 Will pressing the reset button erase my data?
No! The reset button just resets your COMM port. It is the first thing that you should try if you cannot connect to your EM50 data logger and you have the correct port selected. It has a good chance of restoring communications with your logger, and all of your data will be just fine.