Sensor and device maintenance: Winter checklist

ATMOS 41 and 41W all-in-one weather stations

ATMOS 41 and ATMOS 41W all-in-one weather stations are designed for continuous monitoring of environmental and installation quality parameters, including solar radiation, precipitation, air temperature, barometric pressure, vapor pressure, relative humidity, wind speed, wind direction, maximum wind gust, lightning strike counter, lightning distance, and tilt. Individual sensors and support components require regular maintenance.

Anemometer

The accumulation of snow, ice, or frost can negatively impact anemometer measurements. Check the sensor regularly to make sure it is clean and check data often to identify possible problems.

See this app note for more information on ATMOS 41 performance in below-freezing and snowy conditions.

Cable management

Check the connection and integrity of the ATMOS 41 cable. Factors such as rodent damage, heavy machinery or human error can lead to severed cables or poor wiring connections. Use a cable splice kit or replacement connector to repair any damaged or severed cables.

Ensure the cable plug is properly seated in the logger port. Using ZENTRA Utility on your mobile device, scan the logger for the sensor to ensure the logger is retrieving data. Over time, sensor contact may become blocked due to the presence of dust and debris in the logger port. Gently remove and clean the port using a can of compressed air to dislodge any foreign material and swab with isopropyl alcohol if dirt remains.

Rain funnel and downspout

Bird droppings and other debris may affect rain gauge measurements. Check the sensor regularly to make sure it is clean and check data often to identify possible problems. Isopropyl (rubbing) alcohol and a cotton swab work well for cleaning the sensor area. Microfiber rags work well, too. Do not use an abrasive cloth on the sensor surface, as it will scratch.

See the full cleaning instructions for more detail.

Bird deterrent

Installing bird spikes to your ATMOS 41 is strongly recommended to prevent birds from sitting on the edge of the rain gauge and minimize buildup in the rain funnel. During maintenance checks, ensure that all spikes are present. Bent spikes can be straightened with pliers.

Pyranometer

Check the pyranometer regularly to make sure it is clean. Bird droppings and other soiling of the domed sensor surface will cause serious errors in pyranometer readings. The accumulation of snow, ice, or frost may adversely affect the accuracy of solar radiation measurements. Check data often to identify possible problems.

See this app note for more information on ATMOS 41 performance in below-freezing and snowy conditions.

The pyranometer is factory-calibrated. The sensor-specific calibration value can be found on the interior of the rain funnel. METER recommends swapping and calibrating the ATMOS 41 pyranometer with new funnel at least once every two years.

When swapping the ATMOS 41 rain funnel and pyranometer, you will need to enter the new pyranometer calibration value (Cal Factor) into ZENTRA Utility. See instructions for replacing the ATMOS 41 rain funnel and pyranometer. Contact customer support for replacement parts.

RH sensor replacement and calibration

ATMOS 41 barometric pressure and vapor pressure/RH sensors and their respective calibrations are housed on a module that sits behind the circular Teflon membrane in the same housing as the sonic transducers (see Figure 8 in manual).

This module can be replaced in the field. It should be removed and replaced every two years—or annually for some applications—with a new calibrated sensor module. Please contact customer support for new sensor modules/replacement parts and consult the instructions for swapping ATMOS 41 daughterboard.

Instrument levelling and positioning

Keeping an all-in-one weather station level to the ground is critical for rain gauge, anemometer, and pyranometer accuracy. Check horizontal and vertical leveling using the bubble level located underneath the weather station or using X-Y data. The ATMOS 41 and ATMOS 41W must be within ±2° of dead level (0, 0) in both the X and Y directions to accurately measure rainfall and solar radiation. You can also use a ZSC and ZENTRA Utility mobile to display to level the weather station. See the ATMOS manual for recommendations and installation instructions.

The accuracy of wind-direction measurements depends on the orientation of the weather station. Ensure the N-engraved end is still pointing true North using a compass.

TEROS and SOLYX in-ground sensors

Check the connection and integrity of all cables and cable connections. Factors such as rodent damage, heavy machinery or human error can lead to severed cables or poor wiring connections. Use a cable splice kit or replacement connector to repair any damaged or severed cables.

Ensure each cable plug is properly seated in the logger port. Using ZENTRA Utility on your mobile device, scan the logger for the sensor to ensure the logger is retrieving data. Over time, sensor contact may become blocked due to the presence of dust and debris in the logger port. Gently remove and clean the port using a can of compressed air to dislodge any foreign material and swab with isopropyl alcohol if dirt remains.

Devices that are water-filled or saturated—such as the TEROS 32, HYDROS 21, and TEROS 22—should be removed from service prior to freezing weather. Ceramic components and pressure transducers may be damaged by ice formation.

HYDROS 21 water-level monitoring, electrical conductivity, temperature and depth sensors

While freezing is not generally a problem in deep underground well installations, it might be an issue in surface water wells and underground installations above the frost depth. If the sensor is in water, it must not be allowed to experience temperatures below freezing, 0 °C or 32 °F. Ice formation in the pressure transducer cavity will ruin the pressure transducer. Exposing the HYDROS 21 sensor to freezing temperatures with water in the pressure transducer cavity voids the sensor warranty.

PHYTOS leaf wetness sensors

Over time, the accumulation of dust and bird droppings can cause the dry output to rise on the PHYTOS 31 Leaf Wetness Sensor. The sensor should be cleaned periodically using a cloth moistened with deionized water. The sensor should also be cleaned when elevated dry output is detected.

Adding UV protectant will extend the service life of the PHYTOS 31 and is highly recommended. The PHYTOS 31 leaf wetness sensor is designed to withstand typical outdoor radiation and precipitation loads for more than two years. However, application of UV protectant is strongly recommended and is essential when using the PHYTOS 31 in areas with unusually high radiation loads.

McNett UV Tech is the only tested and approved UV blocking system for the PHYTOS 31. The PHYTOS 31 comes pretreated with UV protectant, but METER recommends reapplying McNett UV Tech every 45 days. To apply McNett UV Tech:

1. Wipe sensor clean using water and a clean, soft cloth.
2. Spray soft cloth with UV Tech spray.
3. Rub both sides of the sensor surface with the cloth to apply protectant.

Irrigation sensors

Because the irrigation pressure sensors are plumbed into your irrigation line, possible freeze damage can occur. Please ensure water has been cleared and you take the proper precautions in winterizing your irrigation system.

Tensiometers

Snow accumulation and freezing temperatures can affect the performance of tensiometers in the field. Tensiometers are filled with water, therefore susceptible to freezing. Any tensiometers that might be exposed to freezing temperatures should be removed from service. Refilling the sensor may not be possible under these conditions.

When removing and storing the tensiometer, do not touch the ceramic cup. Skin oil, sweat, or soap residues will influence the ceramic’s hydrophilic performance.

ZL6 data loggers

METER data loggers require minimal maintenance. Winter is a good time to replace your batteries, cable zip ties, and case gaskets. Here’s a troubleshooting video that goes through maintenance items to check.

Battery replacement

You can check the battery level of your ZL6 data logger at any time in ZENTRA Cloud. If you have any doubt in your batteries’ remaining life, replace them as soon as possible. Always replace all six batteries at the same time, and do not mix brands or alkaline with NiMH batteries.

The average battery life expectancy in connected data loggers is 3 to 12 months for alkaline batteries and 2+ years for NiMH batteries with an unobstructed view of the sun, depending on logger configuration. Cold temperatures can reduce battery capacity and affect charge and discharge rates.

Installing or replacing batteries in the ZL6 resets the internal real-time clock. The ZL6 time can be set from ZENTRA Utility, the on-board GPS receiver, and the cellular network. Press the TEST button in ZENTRA Utility after changing the batteries to enable the GPS receiver to acquire a new time and position. Refer to the logger manual for full instructions.

Corroded battery holders

Check the battery holders to make sure they are clean and free of corrosion. If corrosion has formed on the terminals, you can remove it using a cotton swab and vinegar or lemon juice. Severely corroded holders will need to be replaced. Contact support for replacement assistance.

Zip ties and gaskets

Cable zip ties and ZL6 gaskets can be ordered from METER. Replace any cable zip ties and mounting pole connections showing damage. Gaskets should be inspected annually for cracking or other damage that may lead to moisture or debris intrusion into the unit.

Cable management

Check the connection and integrity of all cables and cable connections. Factors such as rodent damage, heavy machinery or human error can lead to severed cables or poor wiring connections. Use a cable splice kit or replacement connector to repair any damaged or severed cables.

Ensure each cable plug is properly seated in the logger port. Using ZENTRA Utility on your mobile device, scan the logger for the sensor to ensure the logger is retrieving data. Over time, sensor contact may become blocked due to the presence of dust and debris in the logger port. Gently remove and clean the port using a can of compressed air to dislodge any foreign material and swab with isopropyl alcohol if dirt remains.

Integrated solar panels

Integrated solar charging panels in the ZL6 data logger and ATMOS 41W all-in-one weather station reduce power maintenance requirements and allow for extended deployments. Solar panels should be cleaned periodically for maximum efficiency. Regular inspection and cleaning of bird droppings, debris, and snow with non-abrasive cloth and water is advised.

Firmware updates

Firmware updates for in-ground sensors are not part of a regular maintenance schedule, and they should not be done unless you are contacted by METER group to do so. If you need to update the firmware on a data logger or ATMOS 41W, the update can be downloaded to a mobile device then transferred to the device in the field using ZENTRA Utility.

Keep software like ZENTRA Utility and ZENTRA Utility Mobile updated on your various devices (laptop, phone, etc).

Software Updates: Check for the newest available version of the ZENTRA Utility. If a newer version is available, a prompt will appear to install the update. The computer or mobile device must be connected to the internet for this feature to work. ZENTRA Utility checks for newer versions of the program each time it launches. It will download these updates in the background automatically.

Logger Firmware Updates: Check for the newest version of ZL6 firmware from METER. If a newer version is available, ZENTRA Utility downloads the firmware in the background.

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