METER 54 Soil Moisture Profile Sensor
Specifications
- Part #: 18510
- Release Date: 3.2023
- Dimensions: 12.5 wide x 8 tall (folded, 8H x 6.25W)
- Colors: CMYK/Full color 4/4
- Printer Type: ELECTRONIC ONLY
Product Usage Instructions
- Unfolding the TEROS 54 User Manual
- To begin using the TEROS 54 User Manual, unfold the manual carefully to reveal the content inside.
- Navigating the Manual
- The manual contains detailed information about the product, including setup instructions, usage guidelines, and troubleshooting tips. Use the table of contents to quickly find the section you need.
- Understanding Color Codes
- Pay attention to the color codes used in the manual. CMYK/Full color 4/4 indicates that the manual is printed in full color using the CMYK color model.
- Accessing Electronic Files
- For electronic versions of the manual, refer to the provided link for the production location. Make sure to access the electronic file from the Publications Library for the most up-to-date information.
FAQs
- Q: Can I print a physical copy of the manual?
- A: No, the TEROS 54 User Manual is designed for electronic use only and should not be printed.
- Q: How can I obtain updates to the manual?
- A: Check the provided link for the production location to access any updated versions of the manual in electronic format.
- Q: Are there any specific guidelines for using the manual?
- A: Follow the instructions provided in each section carefully to ensure proper usage and understanding of the product.
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Document Title:
Description, TEROS 54 User ManualCOVER
Part #
18510
Release Date:
3.2023
Rev Description
00 Initial Release–New 11577 – TEROS 54 UM
01 Change Germany AG to GmbH Updated copyright and .de to .com, also needed to redo
02 PDF export. Completed as part of updates happening to the UM in DCO 23012.
Revision By LAJ KB
EMR
Date 3.22.2023
2.06.24
6.2024
Production Location: http://publications.metergroup.com/Manual%20Covers/18510_TEROS54_Cover.pdf
Working File Path: /SharePoint/Sites/Product Number Library/18500-18599/18510
Dimensions: 12.5″ wide x 8″ tall (folded, 8″H x 6.25″W)
Colors: CMYK/Full color 4/4
Printer Type: ELECTRONIC ONLY
Special Notes: Image below is for reference only (not to scale); Electronic file in Publications Library
INTRODUCTION
Thank you for choosing the TEROS 54 Soil Water Content Profile probe from METER Group.
The TEROS 54 probe is designed to be installed in mineral soils, a variety of growing media, and other porous materials. This manual describes how to use the probe and guides the customer through the probe features.
The TEROS 54 probe is an accurate tool for monitoring volumetric water content (VWC) using capacitance and frequency-domain technology. The sensors use a 70 MHz frequency to minimizes textural and salinity effects that makes the TEROS 54 accurate in most mineral soils.
The TEROS 54 uses four precision-integrated temperature sensors to measure temperature in soil and soilless substrates.
Verify all TEROS 54 components are included and appear in good condition:
1. TEROS 54 probe
2. Protective cap
METER recommends testing sensors with the data aquisition device and software before going to the field.
OPERATION
Please read all instructions before operating the TEROS 54 to ensure it performs to its full potential.
PRECAUTION
METER sensors are built to the highest standards, but misuse, improper protection, or improper installation may damage the sensor and possibly void the manufacturer’s warranty. Before integrating TEROS 54 into a system, make sure to follow the recommended installation instructions and have the proper protections in place to safeguard sensors from damage. If installing sensors in a lightning-prone area with a grounded data logger, see the applicationnote Lightning surge and grounding practices.
2.1 INSTALLATION
This section contains information needed to install the TEROS 54 (Section 2.1.1) and detailed information about how to install in different soil conditions and detailed explanation on how to use the pile (slide) hammer (Section 2.1.2).
2.1.1 INSTALLATION PROCESS
Table 1 contains information needed to install the TEROS 54 and start collecting data.
2.1.2 INSTALLATION METHODS BASED ON SOIL CONDITIONS
This section explains installation methods METER recommends for different soil conditions (Figure 1).
The TEROS 54 probe can only be installed in very loose, sandy, and soft soils without the TEROS 54 auger.
METER recommends using the TEROS 54 auger and slide hammer that are designed specifically for installing the TEROS 54 in compact, firm soil. This method will result in good soil contact.
• The TEROS 54 auger is shaped to prevent soil compaction near the probe elements (Figure 2).
• The slide hammer (Figure 3) consists of four parts: handle, rod, weight (approx. 4 kg [8.82 lbs]), and connector (put on the TEROS 54 head). Because there is a predetermined distance that the slide hammer weight travels when dropped, there is an even distribution of force delivered.
CAUTION When using the slide hammer to install the TEROS 54 probe, please wear proper ear protection to prevent hearing damage because the hammer is quite loud. Please wear gloves to protect hands from being pinched.
CAUTION Never hit the head of the TEROS 54 with a regular hammer. This can damage the probe. Only use the dedicated slide hammer tool from METER.
The following steps detail how to use the TEROS 54 auger:
1. Assemble the auger using the handle and auger tip (Figure 2).
2. Mark the probe length 70 cm on the auger rod.
NOTE: Do not dig deeper than 70 cm to ensure that the probe is in good contact with the soil after installation.
3. Place the auger tip on the ground.
4. Place a level vertically on the rod of the auger.
5. Check the level for the proper angle until the auger tip is in far enough so the angle does not change.
6. Hit the handle gently a few times with a dead blow hammer until the auger tip is 30 cm in the soil.
7. Rotate the auger one revolution to cut off the soil in the borehole.
8. Pull the auger out of the borehole after 30 cm to avoid soil compaction.
9. Remove the soil inside the auger tip.
10. Place the auger back into the borehole to the previous depth.
11. Repeat step 6 through step 10 until the desired depth (maximum is 70 cm) is reached.
After drilling a hole for the TEROS 54, place the TEROS 54 with the pointed side (probe tip) centered over the hole. Press the TEROS 54 as deep as possible into the soil and use the slide hammer (available from METER) to help with installation in firm, compact soils.
Follow the steps and notes below to use the slide hammer for installation:
1. Place the slide hammer vertically and centered on the head of the TEROS 54.
2. Bring the weight to approx. half the drop height.
3. Release the weight.
4. Repeat step 2 and step 3 until the TEROS 54 has reached its intended depth.
NOTE: Please read and consider the following for best results and to avoid damaging the probe.
• The TEROS 54 should be driven approximately 1.0 cm (0.39 in) deep into the soil per drop. Increase the drop height only if the installation comes to a standstill or the probe is being driven less than 1.0 cm per drop. In that case, lift the weight all the way up to its maximum height.
• Allow the weight of the drop hammer to fall by gravity only, do not extend the drop distance or increase the impact force by pushing or using a heavier weight.
• If the TEROS 54 cannot be installed to the intended depth due to rocky compact soil conditions, do not use force, but change the installation location to avoid damaging the probe!
After installing the TEROS 54 in the soil to its maximum installation depth (the head of the TEROS 54 should be approximately 5 mm deep in the soil), attach the protective cap (Figure 5) to the sensor head and connect the TEROS 54 to a data logger (Section 2.2).
Operation
NOTE: Insert the TEROS 54 deep enough into the soil that the head of the TEROS 54 is approximately 5 mm deep into the soil (Figure 4).
2.2 CONNECTING
The TEROS 54 works seamlessly with METER ZENTRA data loggers, and it can also be used with other data loggers, such as those from Campbell Scientific, Inc. For extensive directions on how to integrate the sensors into third-party loggers, refer to the TEROS 54 Integrator Guide.
TEROS 54 probes require an excitation voltage in the range of 4.0 to 24.0 VDC and operate at a 3.6-VDC level for data communication. TEROS 54 can be integrated using
DDI Serial, SDI-12, Modbus RTU, or tensioLINK communications protocol. Refer to the
TEROS 54 Integrator Guide for details on interfacing with data acquisition systems.
TEROS 54 probes come with a 3.5-mm stereo plug connector (Figure 6) to facilitate easy connection with METER loggers. TEROS 54 probes may be ordered with stripped and tinned wires to facilitate connecting to some third-party loggers (Section 2.2.2). A 1.5 M cable is also available for use with an M12 connector.
The TEROS 54 comes standard with a 5-m cable. It may be purchased with custom cable lengths for an additional fee (on a per-meter basis). In some instances, the cable can be extended beyond 75 m by the user, but this is discouraged for a variety of reasons. Please contact Customer Support for more details before extending or splicing cables.
2.2.1 CONNECT TO METER DATA LOGGER
The TEROS 54 works most efficiently with METER ZENTRA series data loggers. 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).
1. Plug the 3.5-mm stereo plug connector into one of the sensor ports on the logger.
2. Using the appropriate software application, configure the chosen logger port for the TEROS 54.
METER data loggers will automatically recognize TEROS 54 probes.
3. Set the measurement interval.
METER data loggers measure the TEROS 54 every minute and return the average of the
1-min data across the chosen measurement interval.
TEROS 54 data can be downloaded from METER data loggers using either ZENTRA Utility or ZENTRA Cloud. Refer to the logger user manual for more information about these programs.
2.2.2 CONNECT TO NON-METER DATA LOGGER
The TEROS 54 can be used with non-METER (third-party) data loggers. Refer to the thirdparty logger manual for details on logger communications, power supply, and ground ports.
The TEROS 54 Integrator Guide also provides detailed instructions on connecting sensors to non-METER loggers.
TEROS 54 probes can be ordered with stripped and tinned (pigtail) connecting wires for use with screw terminals. METER recommends using a 4-pin M12 plug connector and a connection cable with open wires for use with a non-METER data logger using either SDI-12, tensioLINK serial, or Modbus RTU communications protocol.
Connect the TEROS 54 wires to the data logger as illustrated in Figure 7 with the supply wire (brown) connected to the excitation, the digital output wire (orange) to a digital input, and thebare ground wire to ground.
NOTE: The acceptable range of excitation voltages is from 4.0 to 24.0 VDC. To read TEROS 54 with Campbell Scientific, Inc, data loggers, power the sensors from a switched 12-V port or a 12-V port if using a multiplexer.
SYSTEM
This section describes the specifications, components, and theory of the TEROS 54.
3.1 SPECIFICATIONS
MEASUREMENT SPECIFICATIONS
Volumetric Water Content (VWC)
Range
Mineral soil
calibration
0.00−0.70 m3/m3
Apparent
dielectric
permittivity (εα)
1–50 (soil range)
1 (air) to 80 (water)
NOTE: The VWC range is dependent on the media the sensor is calibrated to. A custom calibration will
accommodate the necessary ranges for most substrates.
Resolution 0.001 m3/m3
Accuracy
Generic
calibration
±0.05 m3/m3
typical in mineral soils that have solution EC < 8 dS/m
Medium specific
calibration
±0.02–0.03 m3/m3
in any porous medium
Apparent
dielectric
permittivity (εα)
1–40 (soil range), ±1 (εα) (unitless)
40–80, 15% of measurement
Dielectric Measurement Frequency
70 MHz
Temperature
Range –20 to +60 °C
Resolution 0.03 °C
Accuracy ±0.35 °C from –20°C to 0 °C
±0.25 °C from 0°C to 60 °C
COMMUNICATION SPECIFICATIONS
Output
DDI Serial and SDI-12 communications protocol
3-wire cable version (Figure 6)
4-wire cable version (Figure 10)
RS-485 Modbus RTU and tensioLINK serial communications protocol
4-wire version (Figure 9)
Data Logger Compatibility
METER ZL6 and EM60 data loggers or any data acquisition system capable of 4.0 to
24.0-VDC power and serial interface with SDI-12; and/or RS-485 interface, Modbus
RTU, or tensioLINK communication.
PHYSICAL SPECIFICATIONS
Dimensions
Length 75.0 cm (29.53 in)
Diameter (shaft) 6.0 cm (2.36 in)
Width (head) 11.0 cm (4.33 in)
Operating Temperature
Minimum –20 °C
Maximum +60 °C
Standard Cable Length
5.0 m (stereo plug and stripped and tinned wires)
75.0 m (maximum custom cable length)
1.5 m (M12 connector)
NOTE: Contact Customer Support if a nonstandard cable length is needed.
Cable Diameter
Stereo Plug 4.2 ±0.2 mm (0.16 ±0.01 in)
with minimum jacket of 0.8mm (0.031 in)
M12 Plug 5.5 ±0.2 mm (0.22 ±0.01 in)
with minimum jacket of 1.0 mm (0.039 in)
Connector Size
3.50 mm (diameter)
14.4 mm (diameter M12)
Connector Types
Stereo plug connector or stripped and tinned wires
4-pin M12 connector or stripped and tinned wires
Conductor Gauge
Stereo Plug
M12 Plug
22-AWG / 24-AWG ground wire
22-AWG
ELECTRICAL AND TIMING CHARACTERISTICS
Supply Voltage (power to ground)
Minimum 4.0 VDC
Typical NA
Maximum 24.0 VDC
Digital Input Voltage (logic high)
Minimum 2.8 V
Typical 3.6 V
Maximum 5.0 V
Digital Input Voltage (logic low)
Minimum –0.3 V
Typical 0.0 V
Maximum 0.8 V
Digital Output Voltage (logic high)
Minimum NA
Typical 3.6 V
Maximum NA
Power Line Slew Rate
Minimum 1.0 V/ms
Typical NA
Maximum NA
Current Drain (during 500-ms measurement)
Minimum 3 mA
Typical 35 mA
Maximum 50 mA
Current Drain (while asleep)
Minimum 0.03 mA
Typical 0.1 mA
Maximum NA
Power-Up Time (DDI Serial)
Minimum 500 ms
Typical NA
Maximum 800 ms
Power Up Time (SDI-12)
Minimum NA
Typical 1,000 ms
Maximum NA
Power Up Time (SDI-12, DDI Serial disabled)
Minimum 500 ms
Typical 600 ms
Maximum 800 ms
Measurement Duration (4 depths)
Minimum 500 ms
Typical NA
Maximum 800 ms
COMPLIANCE
EM ISO/IEC 17050:2010 (CE Mark)
3.2 COMPONENTS
The TEROS 54 consists of the probe and a protective cap for the thread of the probe head.
The TEROS 54 measures the volumetric water content (VWC) and soil temperature at four defined depths: 15 cm, 30 cm, 45 cm, and 60 cm. Each depth represents the center point of the measuring sensors. At every measuring depth, the TEROS 54 is equipped with four independent VWC sensors for a 360° measurement (Figure 19). Because the TEROS 54 is equipped with four sensors per depth, it gives an accurrate representation of the soil at that depth.
For the best output, the measured values of all four sensors are calculated together. If the measurement at one of the four sensors is disturbed, for example, because a root or a stone interferes with the sensor, the 360° measurement coverage of the TEROS 54 compensates for this. In this case the other three sensors provide correct data.
The most accurate measurement results are obtained very close to the TEROS 54 shaft in each area between the wings (Figure 18). As the distance from the shaft increases, the strength of the sensors also decreases. The measuring volume is approximately 300 cm³ per depth.
SERVICE
This section describes the calibration and maintenance of the TEROS 54. Troubleshooting solutions and customer service information are also provided.
4.1 CALIBRATION
METER software tools automatically apply factory calibrations to the sensor output data. Calibration by the customer is not provided. Please contact Customer Support if a TEROS 54 needs to be recalibrated.
This section includes the mineral soil and dielectric calibrations for TEROS 54, where Θ is the VWC (in m3/m3 ), ε is dielectric and RAW is the raw sensor output when read with a METER or third-party data logger.
The TEROS 54 is not sensitive to variation in soil texture and electrical conductivity (EC) because it runs at a high measurement frequency. Therefore, its generic calibration equation should result in high accuracy for most instances; 0.05 m3/m3 for most mineral soils up to 8 dS/m saturation extract.
Its calibration equations are shown below for mineral soil and dielectric permittivity. However, for added accuracy, customers are encouraged to perform soil-specific calibrations. Please refer to Soil-specific Calibrations for METER Soil Moisture Sensors on the METER website (meter.ly/how-to-soil-specific-calibrate) to calibrate the TEROS 54. For more information on how to calibrate sensors or to learn about METER calibration service (calibrations performed for a standard fee), contact Customer Support.
4.1.1 MINERAL SOILS
According to METER tests, a single calibration equation will generally suffice for most mineral soil types with ECs from 0 to 8 dS/m saturation extract. VWC Θ is given by
Equation 1:
Θ (m3
/m3
) = 1.8543×10-8 × RAW3
– 4.1231×10-5 × RAW2
+ 3.1015×10-2 × RAW − 7.7224
Equation 1
A third order polynomial is used for the mineral soil calibration because it provides the best VWC predictions in the VWC range found in mineral soils, but this equation reaches a maximum at approximately 0.70 m3/m3 in pure water. To display data on a scale from 0.0 to 1.0 m3/m3 , VWC should be modeled with a quadratic equation (which would result in a 1.0 m3/ m3 in water). However, METER does not recommend this for mineral soils because the VWC range found in mineral soil often makes the calibration less accurate.
4.1.2 APPARENT DIELECTRIC PERMITTIVITY
Apparent dielectric permittivity εa can be used to determine VWC using external published equations such as the Topp equation (Topp et al. 1980). Dielectric permittivity is also used for calculating pore water EC. Dielectric permittivity is given by Equation 2:
4.2 MAINTENANCE
TEROS 54 may be returned to METER for maintenance in the following areas: system inspection, parts replacement, and instrument cleaning. Replacement parts can also be ordered from METER. Contact Customer Support for more information. The nominal lifespan for outdoor usage is 10 years, but the lifespan can be substantially extended by proper and careful usage and by protecting the sensor against ultraviolet (UV) radiation and frost.
NOTE: Do not use any solvents for cleaning TEROS 54.
4.3 TROUBLESHOOTING
Table 2 lists common problems and their solutions. If the problem is not listed or these solutions do not solve the issue, contact Customer Support.
Table 2 Troubleshooting the TEROS 54
Documents / Resources
 | METER 54 Soil Moisture Profile Sensor [pdf] User Manual 18510, 54 Soil Moisture Profile Sensor, 54 Soil, Moisture Profile Sensor, Profile Sensor |