Attachment 4 - SCAN Maintenance Manual v3 2022.pdf

National Water and Climate Center

SCAN Program

Soil Climate Analysis Network (SCAN) Station Maintenance

Cell Modem Antenna

Lightning Dissipator

Relative Humidity & Air Temperature Sensor

Liquid Precipitation Gage

Wind Speed & Direction Sensor

Solar Radiation Sensor

NEMA

box

Soil Moisture & Temperature Sensors

Solar Panel

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Revision History This manual will be updated annually or periodically during the year when equipment is changed or upgraded.

Version Description Date

1.0 Initial release June 2020

2.0 Second release January 2021

3.0 Third release June 2022

USDA is an equal opportunity provider, employer, and lender.

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Contents Revision History

Overview

Station Design Evolution

Station Maintenance Preparation

Pre-Trip Planning Report

Post-Visit Communication

Suggested Toolkit

Station Maintenance Checklist

Detailed Sensor Maintenance Activities

SCAN station sensors and components’

Shelter Building: 4’ x 4’ x 8’

Tipping Bucket Precipitation Gage Sensors

Air Temperature/Relative Humidity Sensor

Solar Radiation Sensor

Wind Speed/Wind Direction Sensor

Soil Moisture/Soil Temperature Sensors

Station Battery

Internal Relative Humidity Sensor

Station Grounding

Solar Panel Regulator

Cellular Modem

Cellular Antenna

Appendix A: Example Site Inventory

Appendix B: Survey 123 Manual

Appendix C: Wiring Diagram for New Sensor

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Overview The Soil Climate Analysis Network (SCAN) began as a soil moisture/soil temperature pilot project of the Natural Resources Conservation Service (NRCS) in 1991 to provide data in support of natural resource assessments and conservation activities. SCAN operates a comprehensive, nationwide soil moisture and climate information network, focused on agricultural areas, with over 200 stations providing data in near real-time.

SCAN stations collect hourly information on soil moisture content and soil temperature at standard depths (2, 4, 8, 20, and 40 inches), air temperature, relative humidity, solar radiation, wind speed/direction, and liquid precipitation.

Station Design Evolution SCAN stations vary in design depending on the time of installation and site characteristics. The first-generation stations were designed with a 4-foot by 4-foot by 8-foot shelter, along with a standalone meteorological tower and separate electronics enclosure (NEMA).

First-generation SCAN station with building

Located on the right side of the photo above is an older-style precipitation gage which is no longer used.

Some of these gages have been replaced whereas other stations will still have them.

The second-generation SCAN stations are more compact, with one 20-foot tower holding an upper enclosure containing the communication device and data logger, and a lower enclosure holding the batteries. The

4 | P a g e R e t u r n t o C o n t e n t s cross-arms and sensors are attached to the tower and the soil moisture/soil temperature sensors are located within 15 feet of the tower.

WARNING: You must be certified and have the necessary safety equipment before climbing any tower.

Second-generation SCAN station with one tower

The current third-generation SCAN stations have a 10-foot tower to accommodate cellular or GOES satellite communication, but otherwise use the same configuration of sensors as second-generation stations.

Third-generation SCAN station

Details on the differences in stations are further described in this manual.

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Station Maintenance Preparation It is important to plan for and gather station information before beginning maintenance on a SCAN station.

This section describes what is required for this phase of the process.

Pre-Trip Planning Report The SCAN Coordinator will generate a monthly list of prioritized maintenance needs for the SCAN network.

From this needs list, the Logistics Management Coordinator will propose a Monthly Maintenance Plan to address the highest priority maintenance concerns. This maintenance plan must be approved by the SCAN Coordinator.

After the Monthly Maintenance Plan is approved, a Pre-Trip Planning Report for each maintenance trip will be created by the Logistics Management Coordinator. This pre-trip report will be sent to the staff conducting the work as well as the SCAN Coordinator and Data Editor.

The Pre-Trip Planning Report should include the following:

1. Travel Logistics Plan (including details about travel, lodging, vehicle, tools, equipment, safety PPE, site access information).

IMPORTANT: All SCAN station combination locks are set to 1991 - the year that SCAN started.

2. Site Location Information (with contact information included) - Most stations are located on Government or university property; however, some stations are located on private land.

IMPORTANT: If located on private land contacting the landowner is required prior to accessing the station. Always contact the landowner prior to going to the SCAN station location.

3. Site Inventory. (See Appendix A)

4. Notes and photos from last maintenance visit.

5. Maintenance Needs: A description of work to be performed and additional instructions if replacement of equipment is required.

6. Equipment List: based on maintained needs - develop list of equipment needed for trip. Include ship from and ship to (locations and dates) information.

NOTE: A Suggested Toolkit and tools list is on page 6.

7. Site access map and mileage log.

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Day-of Site Visit Communication

• On the day of a station visit, the maintenance staff must submit appropriate Survey123 Form with before and after pictures, updated inventory (sensors replaced), site needs (e.g. sensors out of calibration, site damage), and any telemetry changes

• Email or text the SCAN Data Editor and SCAN Coordinator if there are unforeseen issues or changes to the maintenance schedule.

• Use Survey123 to note any updates/changes to a station’s inventory, contact information, or mileage log, site status, etc.

• Send unused supplies and equipment to:

NWCC SCAN Data Editor 245 North Jimmy Doolittle Road, Door B, Salt Lake City, UT 84116

Suggested Toolkit Select from this list based on what is outlined in the Pre-Trip Planning Report (work with SCAN Coordinator to coordinate transfer of tools).

1. Screwdrivers (standard slotted, Philips, multiple sizes)

2. Pliers (pump, channel locks, or robo grips)

3. Battery-powered drill, bits, and drivers (1/4 inch hex head)

4. Self tapping screws ½ inch long with ¼ inch hex head (31JJ46 Item number at Grainger)

5. Hammer and hole alignment tool (you could also use a Philips head screwdriver to get the antenna base holes aligned with the antenna top)

6. Shovel and Pulaski to dig the trench for the soil moisture sensors

7. Soil auger for installing soil moisture sensors

8. T-handled 40” soil probe installation tool

9. Knife or box cutters

10. Adjustable wrench with insulated handle, open and closed end (ratchet) wrenches (1/4, 1/2, 1/8, 3/8, 7/16, 1/2, 5/8 inch), wire strippers and a set of Allen wrenches (standard and metric)

11. Electrical tape or UV-resistant zip ties

12. Labels for soil sensors

13. Duct seal

14. Desiccant

15. WD40 lubricant

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16. Compass. determine what the magnetic declination is for your site, so you can adjust the compass reading to True North-South when putting in the antenna base

17. Small level to ensure the antenna tower base is vertical, the cross-arms are level, and to level the rain gage

18. Volt meter

19. Field calibration device for rain gage

20. Handheld device that measures air temperature, relative humidity, and wind speed for field verification

21. Handheld device that measures solar radiation for field verification

22. Tape measure (20 foot)

23. 8-foot ladder (or Little Giant folding style) or appropriate equipment to access cross-arms

24. Soft bristle brush, pipe brush, paper towels, cloth, mild detergent, Compressed air, isopropyl alcohol, and water for cleaning equipment

25. Battery cleaner and brush

26. Terminal Battery Protector or dielectric grease

27. Vegetation removal equipment (weed eater, weed whacker, loppers, saw, etc.)

28. Personal Protective Equipment (gloves, helmet, climbing gear, sunscreen, closed toed boots, insect repellent, wasp and hornet spray)

29. Sharpies

30. Trash bag

31. First Aid Kit

32. Water and food

33. Cellular phone with Loggerlink app installed

Direct questions to:

SCAN Coordinator 245 North Jimmy Doolittle Road, Door B, Salt Lake City, UT 84116

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Station Maintenance Checklist Upon arrival at a SCAN station, the maintenance staff should assess the station for safety concerns and damage. After the initial assessment, photograph any damage and document site changes. Use this checklist and Survey 123 (see Appendix B) as you complete the following tasks:

Take pre-visit photos of exterior from multiple angles, making sure to photograph all equipment and vegetation.

Open shelter door (if applicable) following shelter building instructions on page 12.

Open all NEMA electronics enclosures (use caution for insects).

Take pre-visit photographs of interior of NEMA enclosures, including wiring configurations.

Check every item in Inventory tab of Survey123 to ensure it is accurate, including serial numbers.

Make necessary changes on the Inventory tab.

Check all equipment for water, animal, or electrical damage. Take photographs of any damage.

Inspect all wiring in NEMA boxes, ground wires and clamps, and wires on tower – inspect for damage to any wire casing or any exposed wires.

Check the batteries for corrosion and clean if indicated (refer to page 31). Check battery voltage and replace battery if voltage is below 12.3v. If battery voltage is above 14.8v, replace the solar panel regulator.

Check solar panel for dirt build up. If dirty, clean solar panel using a paper towel and water.

Clear any vines and other plant growth from the antenna tower, NEMA boxes, and surrounding area. Be cautious with any vines, as they could be poison ivy or poison oak. Use a weed eater or equivalent to remove overgrown vegetation within fence or within 6 feet of tower and sensors.

Replace sensors and equipment as instructed in pre-trip planning report.

Verify the type of precipitation gage at site with the Survey 123 and replace any Texas Electronic gage with a HSA TB4 gage (refer to page 14).

Clean screen, funnel, and siphon on precipitation gage. Check to make sure O-ring is present and intact - replace if needed. Apply a light coating of valve grease on O-ring before reassembling the funnel.

Check and adjust level on precipitation gage. Record serial number before re-assembling gage.

Use Field Calibration Device to pour 200ml of water through tipping bucket gage slowly and verify that the number of tips is between 24-26.

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Check air temperature shield for cleanliness and check gills for vegetation or insects. Clean or replace shield if dirty or damaged.

Confirm air temperature/relative humidity sensor type. If HMP45 or HygroClip 2, replace with HMP155 and appropriate 14-gill shield (refer to page 17).

Replace temperature/RH sensor head. Package old sensor and send to SCAN facility for calibration.

Check solar radiation sensor for dirt build-up and replace/clean if dirty. Verify/adjust level so that it is horizontal (refer to page 19).

Check wind speed propeller blades, sensor body and tail fin for damage. If sensor is dirty, clean using a paper towel and water.

Replace wind speed bearings - refer to page 201. Photograph internal bearings prior to reassembly of wind speed sensor.

Verify that the wind speed sensor is level.

Verify (with a compass not a phone) the wind speed direction sensor to ensure black box is pointing due South.

If site has a cell modem and a CR1000(X) datalogger, connect to datalogger via Loggerlink app on cell phone using the IP address of the modem. If site has another configuration, contact SCAN staff to assist with verification steps below.

Verify solar radiation reading with field reading from handheld unit.

Verify air temperature and RH sensor readings with field readings from handheld unit.

Verify wind speed and direction readings with field readings from handheld unit and compass.

Verify all sensor readings on datalogger are within reasonable range, including soil moisture and temperature sensor readings.

Replace desiccant inside NEMA enclosure.

Take post-visit photos of inside of NEMA enclosures before locking all NEMA boxes.

Take post-visit photos of exterior at some locations as pre-visit photos, making sure to photograph all equipment and vegetation.

Pack out all trash from site.

When finished, return all used and unused equipment back to the SCAN Coordinator at the SCAN facility. SCAN Coordinator, 245 North Jimmy Doolittle Road, Door B, Salt Lake City, UT 84116

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Detailed Sensor Maintenance Activities This section contains detailed maintenance steps for each sensor or component at the SCAN station. Here are the sensors and the page on which the maintenance is described:

1. SCAN station sensors and components’: page 11

2. Shelter Building: 4’ x 4’ x 8’: page 12

3. Tipping Bucket Precipitation Gage Sensors : page 13

4. Air Temperature/Relative Humidity Sensor: page 17

5. Solar Radiation Sensor: page 20

6. Wind Speed/Wind Direction Sensor: page 24

7. Soil Moisture/Soil Temperature Sensors: page 25

8. Station Battery: page 31

9. Internal Relative Humidity Sensor: page 34

10. Station Grounding: page 35

11. Solar Panel Regulator: page 36

12. Cellular Modem: page 37

13. Cellular Antenna: page 38

IMPORTANT: Before replacing any sensor, unplug the power cable to the data logger to ensure that any contact with a power source does not damage the data logger.

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SCAN station sensors and components The photo below shows the configuration of sensors and components for a third generation (current) SCAN station. Soil moisture and temperature sensors are typically at 2-inch, 4-inch, 8-inch, 20-inch, and 40-inch depths. Antennae may have been removed from some towers.

Cell Modem Antenna

Lightning Dissipator

Relative Humidity & Air Temperature Sensor

Liquid Precipitation Gage

Wind Speed & Direction Sensor

Solar Radiation Sensor

NEMA

box

Soil Moisture & Temperature Sensors

Solar Panel

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Shelter Building: 4’ x 4’ x 8’ Shelter buildings are typically only installed on older, first-generation SCAN stations.

IMPORTANT: Be VERY cautious and carry wasp spray when opening the door to the shelter because wasp nests can be inside and around the shelter structure.

The lower door is typically secured with a long bolt through eye holes.

1. Lift the bolt out to open the lower door. The large NEMA electronics enclosure will be inside.

2. Use a large flathead screwdriver to open the NEMA enclosure door to access the data logger and communication device.

Generally, the shelter also houses batteries, a short ladder, soil auger, and tile spade. Not all shelters will have a shovel inside.

If the station has a shelter, there will be a 10-foot meteorological tower that has all the above-ground sensors, and another small NEMA electronics enclosure which is used to wire the soil moisture/soil temperature sensors.

Shelter building

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Tipping Bucket Precipitation Gage Sensors These sensors, typically located on the lower cross-arm of the tower, can generally be accessed from the ground. However, some stations will require a step ladder to reach the sensor. For sites with significant wind the tipping buckets can be mounted on a pole in the ground.

Two Types of Tipping Bucket Gages There are two types of tipping bucket precipitation gages used in SCAN (phot below). The older Texas Electronics gage (left) with a 6-inch opening is being replaced by the HSA TB4 gage (right) with an 8-inch opening.

Tipping bucket gages. Older version left, newer version right

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HSA TB4 Sensor Maintenance If the HSA TB4 precipitation gage is not working, it is typically due to a plug in the siphon. This procedure describes how to fix the plugging issue.

To remove the HSA TB4 gage:

Loosen Allen screws to remove top of gage

Follow instructions from the manufacturer at https://hydrologicalusa.com/blog/index.php/2017/08/03/15-easy-steps-to-keeping-your-tipping-bucket-rain-gauge-in-top-working-condition/

Next, watch the tipping bucket rain gage maintenance video (https://youtu.be/pZTeR1ujhIE ) and then follow these maintenance steps:

IMPORTANT: Note that not all the steps from the video are included here:

1. Use 5/32-inch Allen wrench to loosen the three bolts (or Allen key supplied with the rain gage) to loosen the bolts and remove the funnel body. Look down on the gage to see the rocker mechanism and leveling bubble.

Inside of HSA TB4 gage gage with leveling bubble and serial number https://hydrologicalusa.com/blog/index.php/2017/08/03/15-easy-steps-to-keeping-your-tipping-bucket-rain-gauge-in-top-working-condition/ https://hydrologicalusa.com/blog/index.php/2017/08/03/15-easy-steps-to-keeping-your-tipping-bucket-rain-gauge-in-top-working-condition/ https://youtu.be/pZTeR1ujhIE

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2. The gage sits on a leveling plate that has three bolts with one nut below the gage and one nut above the gage. The top nut secures the gage to the leveling plate and the bottom nut adjusts the level of the gage.

3. Using 7/16-inch wrench, loosen all three top nuts and then adjust the bottom nuts to level the gage using the level bubble on the gage itself.

4. Once the gage is level, tighten the top nuts to secure the gage. Do not overtighten these nuts. Just make sure they are snug.

5. The serial number of the gage is located on the base unit on a white placard. Record the serial number for entry into the Survey123 form.

Leveling plate adjustment for Hydrological Services gage

6. On the funnel body, push the siphon assembly down from the top of the gage and simultaneously pull from underneath to remove siphon assembly. Check for black tape attaching the siphon assembly to the funnel.

7. Remove the wire screen from the siphon assembly and clean it with water and a paper towel. Be careful not to damage the wire screen or plastic cage.

8. If the siphon has a brass tube, use a 10 mm wrench to undo the siphon nut, then clean siphon body with isopropyl alcohol. If the siphon tube is plastic and can’t be removed from the siphon, clean the whole assembly as one unit.

9. Use compressed air to remove stuck particles from inside the siphon tube or the siphon assembly.

10. Once cleaned, reassemble the siphon assembly (tighten the nut gently), then add the wire screen and plastic cage.

11. Inspect the O-ring on the outside of the siphon assembly for cracks or brittleness. Replace O-ring if needed. Apply plumber’s valve grease to preserve O-ring and improve seal.

12. Use spray cleaner (like Windex or Simple Green) to clean the siphon enclosure funnel.

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13. Insert siphon assembly by pushing the unit into the funnel from underneath. It is just held in place by friction from the O-Ring. If the fit is loose, use black tape to secure the assembly from below.

14. After the gage is cleaned and level, place the gage funnel assembly on the base of the gage and tighten the hex head bolts. The nuts are retained in a plastic housing that can crack or break – so tighten bolts gently.

Siphon assembly: screen, brass tube, and O ring

Tipping Bucket Gage Calibration (required for all types of gages)

To accurately calibrate the gage a known volume is used to verify the gage is recording properly.

Use Field Calibration Device to pour 200ml of water through tipping bucket gage slowly and verify that the number of tips is between 24-26 (either by counting the audible tips or by watching the precip total on the datalogger readout).

IMPORTANT: It is critical to record the number of tips encountered during the calibration procedure. It is also important to note if rain occurred during the visit. The internal count in the datalogger is interrupted during site maintenance, so knowing both of these things is very important to keep an accurate water year total.

Sensor repair or replacement If you need to replace the gage:

1. To replace a HSA TB4 gage, remove the three nuts from the gage and remove it from the mounting hardware.

2. Record the serial number of the sensor that you remove and the serial number of the new gage for entry into the Survey123 form.

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3. Install the new gage and make sure it is level by adjusting the bottom nuts and watching the level bubble inside the gage. After leveling, tighten the top nuts on the leveling plate to secure the gage.

4. Wire the sensor by running the black cable through the small hole on the bottom of the gage and then using a small screwdriver to attach the two leads to the first two holes on the terminal strip.

5. After the gage is level, place the gage funnel assembly on the base of the gage and tighten the hex head bolts. The nuts are retained in a plastic housing that can crack or break – so tighten bolts gently.

Air Temperature/Relative Humidity Sensor This sensor is located on the lower cross-arm and typically requires a step ladder to get to the sensor.

There are two types of air temperature/relative humidity sensors. The HygroClip 2 sensors are being phased out and should be replaced by HMP155.

IMPORTANT: Ensure you know what kind of sensor is installed at the station you are going to, so you can replace the sensor type if needed.

These HMP 155 sensors are located inside a 14-gill shield. You will need a pair of pliers to loosen the compression nut that secures the sensor to the shield. The compression nut is below the shield, where the sensor enters the shield. Loosen the nut and remove the sensor head.

HMP155 gill shield with locking nut

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The maintenance procedure is to replace the HMP155 sensor head.

1. First, slide down the white rubber cover at the base of the sensor to expose the junction between the cable body and the sensor head.

2. Remove the sensor head of the HMP155 by unscrewing it from the cable body. Use your fingers to unscrew the head.

3. After recording the serial number of the new sensor head, align the new sensor head and tighten with fingers to the cable body.

Hydroclip head and base

4. After removing the yellow protection cap from the end of the sensor, insert sensor assembly into the 14-gill shield and tighten the compression nut with pliers until the sensor is very secure and doesn’t move when tugged on.

5. Slide the white rubber cover back over the junction between the cable body and the sensor head.

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Dirty (left) and clean installed (right) Air temperature/relative humidity shield

The 14-gill shield that protects the air temperature/ relative humidity sensor must be clean and white for it to function. If it is not clean and white, it needs to be cleaned or replaced.

1. Clean the shield with spray cleaner (like Windex or Simple Green) and a soft brush or towels.

2. If replacing the shield, use a half-inch ratchet wrench to remove the locking nuts.

3. Before replacing the shield, remove the sensor from the shield first.

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Wind Speed/Wind Direction Sensor The wind sensor is on the upper cross-arm, opposite the solar radiation sensor. The black box on the wind sensor must face True South.

Important: Use the following website to calculate True South:

https://www.ngdc.noaa.gov/geomag/calculators/magcalc.shtml?useFullSite=true

Wind Speed and Direction Sensor and the black box that is always pointing True South

1. A four-blade propeller measures the wind speed. Ensure that none of the blades are damaged or broken off.

2. Check the overall sensor body. There is a tail fin at the opposite end, so the sensor can move with the wind and give the direction.

3. Clean the sensor with water and paper towels.

Level sensor IMPORTANT: It is critical that the sensor is level, otherwise the wind direction will not be accurate.

1. To check the levelness of the sensor, place a level on the cross-arm and a level on the black box of the sensor itself.

2. If needed, use a 3/16-inch Allen wrench to loosen the Hollander clamps on the tower leg to make necessary adjustments until the sensor is level.

3. Once the sensor is level, retighten the Allen screws on both Hollander clamps. Usually the cross-arm will move slightly as you tighten down on the Allen screws, so you will have to adjust the pipe accordingly.

https://www.ngdc.noaa.gov/geomag/calculators/magcalc.shtml?useFullSite=true%20

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Hollander clamp

Bearing replacement Anemometer bearings should be replaced on an annual basis.

1. Remove old bearings:

a. Unscrew nose cone assembly (including propeller). Make sure orange O-ring remains inside assembly.

b. Loosen set screw on magnet shaft collar using a 1/16” allen wrench (there should be one at every site in small ziplock bag inside NEMA box).

c. Remove magnet and shaft collar.

d. Slide propeller shaft out of nose cone assembly.

e. Remove front bearing cap which covers front bearing.

f. Remove both front and rear bearings from nose cone assembly.

2. Use propeller shaft to remove the bearing flange by poking it from the other side. Install new bearings:

a. Gently insert new front and rear bearings into nose cone with finger (you can use propeller shaft to help gently press fit bearings into place)

b. Replace front bearing cap.

c. Carefully slide propeller shaft through bearings. Hold the rear bearing in place while inserting the propeller shaft, as it may come loose.

d. Place magnet and shaft collar on propeller shaft allowing 0.5 mm (0.020") clearance from rear bearing using black plastic positioning tool (should be in ziplock found in NEMA box)

e. Tighten set screw on magnet shaft collar using 1/16” allen wrench.

f. Confirm orange O-ring is still in place inside nose cone.

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g. Carefully screw nose cone onto main housing until O-ring seal is seated. Be certain threads are properly engaged to avoid cross-threading.

h. New bearings will make noise for the few minutes of use – this is normal.

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Sensor replacement If the sensor is not operational, it will need to be replaced.

IMPORTANT: Before replacing any sensor, make sure you unplug the power cable to the data logger to ensure that any contact with a power source does not damage the data logger.

1. Remove power from the data logger.

IMPORTANT: DO NOT LOOSEN OR REMOVE THE LOWER BLACK LOCKING CLAMP. THIS CLAMP HAS A SMALL

VERTICLE TIP.

2. Using a flathead screwdriver or hex nut driver, loosen the top hose clamp.

3. Lift the sensor off the vertical pipe.

4. Place the new sensor on the vertical pipe. Pay special attention to the small notch which will seat inside the lower locking clamp. On the vertical pipe, there is a black mounting ring still attached with a hose clamp. DO NOT REMOVE THIS.

5. Remove the electrical tape and zip ties from the cross-arm and down the antenna tower leg.

6. Route new sensor wiring, while removing the old sensor wiring

7. Remove the duct seal from the bulkhead adapter from the inside and outside of the upper NEMA enclosure.

8. Locate the wires inside the NEMA and cross reference the color code with the wiring diagram. (See Appendix C).

9. Record the serial number of the old sensor. You can find it on the black box or on the wire end where the wires were attached to the data logger or wiring strip. Record the new sensor serial number on the metadata sheet

10. Loosen the screws and pull the old sensor wires out from the data logger or wiring strip and remove the wires from the NEMA.

11. Using the wiring diagram, secure the new sensor wiring to the appropriate terminals, and secure the screws. (See Appendix C).

12. Secure the wire from the sensor, place the wire on the underneath side of the cross-arm and secure it with electrical tape or zip ties.

13. Wrap up the excess wire and secure it with electrical tape or zip ties. Replace the duct seal to the inside and outside of the bulkhead connector.

14. Plug the power cable back into the data logger.

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Solar Radiation Sensor The solar radiation sensor is always mounted toward the South, facing upward on the upper cross-arm.

1. Use a ladder to access the solar radiation sensor.

2. Inspect the white part of the sensor and if dirty, clean with a soft damp cloth.

3. Adjust mount until sensor is level.

Sensor replacement

1. Record the serial number of the current sensor and the new sensor for entry into Survey123 form.

2. Remove the current sensor by unscrewing the cable connector which is about 9” from the sensor itself. There is a black flathead plastic bolt that holds the solar rad sensor to the leveling plate.

Unscrew this by inserting a screwdriver from below through the hole in the leveling plate.

3. Install the new sensor by lining up the sensor on the black bolt and tightening from below.

4. Level the sensor and remove the green protector cap.

5. Attach the sensor pigtail to the sensor cable at the cable connector.

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Soil Moisture/Soil Temperature Sensors

Site layout with separate Soils NEMA enclosure The location of soil sensors varies based on layout of the station. The stations with a building have soil sensors placed inside a fenced area. The soil sensor leads junction in a small NEMA enclosure, located on a galvanized pole in the ground, holds two wiring strips: one side is reserved only for soil sensors.

Multiconductor wiring cables extend from the box to the building and the inside the large NEMA enclosure.

Most of these stations use analog soil sensors and have multiple wires for each depth.

Soils NEMA enclosure

Inside this small NEMA, the wire should be marked as to which depth or position the sensor wire is going to on each wire. Notice the white labels attached to the wire. The white labels indicate which sensor goes to which depth.

Some of the NEMA enclosures also have this labeled on the NEMA backplate. Usually from the left side of the box and top of the wiring strip will be the 2-inch sensor (1). The wires will be Blue, Brown, Green, White, Yellow and Black together. Then this pattern repeats for each depth. The typical depths for the soil sensors are 2-inch, 4-inch, 8-inch, 20-inch, and 40-inch. A few stations may have two different stacks of soil sensors, but the procedure would be the same.

Site layout without separate Soils NEMA enclosure The newer site layouts omit a separate soil junction box, and the soil sensor leads run strait into the main NEMA box. Some SCAN stations have analog soil moisture/soil temperature sensors that are wired directly into a multiplexor in main site NEMA box. This is typical at SCAN sites with the one-tower layout.

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Main NEMA enclosure typical of newer SCAN sites

Changing sensors at either site layout

1. Identify which sensor needs to be replaced from inside the NEMA enclosure.

2. Starting at the NEMA enclosure, locate the conduit pipe carrying the soil sensor wires (the conduit that leads away from the shelter, not toward it).

3. Carefully follow the conduit out until the conduit stops. From there you should see the wires. Follow the wires out to where the sensors are located.

4. Excavate the soil from around the wires carefully with a shovel. Use a hand trowel or large flathead screwdriver to expose all the wires.

5. Determine which sensor wire is the one that requires replacing by pulling on the wire from inside the NEMA and watching which wire moves outside where the soil sensors are buried.

6. Do not try and dig up malfunctioning soil sensors – cut the wire and leave the sensor installed as is. You will need a cable cutter or a pair of side cutters to cut the wire from the bad sensor.

IMPORTANT: If you are replacing multiple sensors, it is important to identify each new sensor and its depth. Use a black sharpie to write on the soil sensor the depth to which it will be placed (2, 4, 8, 20, or 40-inches). At the other end, use wire label and identify each depth on each cable. Record the serial number in Survey123

7. Use the cut leads to fish the new sensor wire back to the NEMA enclosure. Overlap the two wires at least four inches and tape the two sections of wire together using electrical tape. Make sure there are no kinks in the wire. This will make it easier to pull the new wires through the conduit. Make sure there is a label on the wire identifying the depth of the sensor.

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8. For the 2, 4, 8, and 20-inch sensors, you will need to dig a small hole down to the desired depth you need. The hole should be no larger than 12 inches in diameter. If you are only replacing the top three sensors, the hole can be smaller in diameter. The goal is to not disturb the soil as much as possible with the hole you are digging. Install at least a foot away from the original stack of soil sensors

9. Once you have the excavated to the correct depth, place the new sensor at the correct depth by using a tape measure. The depth of the sensor is measured from the center tine of the sensor to the top part of the soil.

8” soil sensor insertion and placement -note body of sensor fully supported by undisturbed soil material

10. Place the sensor in horizontally into the hole, in the undisturbed side wall. If you are replacing multiple sensors in the same hole, stagger the positions of the new sensors going from the deepest to the shallowest. It is also best to dig a “step” into the pit face and install the sensor so that the sensor body (white part) is supported by undisturbed soil. It is preferred to backfill in stages, packing as you go carefully with your hand or foot. For an average person, packing with their foot approximates an average soil bulk density. By doing the two above-mentioned things, we minimize the likelihood of differential settling, which causes sensor movement.

11. If you are replacing the 40-inch depth sensor, use the soil bucket auger to go down to 39-inches. This sensor will be placed in the vertical position.

12. Use a probe installation tool, PVC pipe, or the soil auger pipe to push the sensor into place and make sure it is seated in the hole. Backfill carefully as shown in picture below using a long-handled tool.

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40” soil sensor insertion and placement -note vertical placement in augured hole

40” soil sensor insertion and placement -note careful backfill and packing technique

13. Take pictures of the new soil sensor placement.

14. Put the soil back in the hole carefully, packing with your hand as you go. Make sure that you fill in underneath the new sensor, so it will not pull back out from its position.

15. Continue to fill the hole all the way up to the top. You should have a small trench for the wires to be covered up after pulling them into the NEMA box.

Wiring for sites with separate Soils NEMA enclosure

1. Unwire old wire from the wiring strip.

2. Cut each wire individually for length. Make sure you replace the wire label marker for the depth before cutting any of the wires.

3. Using your knife, carefully cut the outside of the cable sheath and remove the sheath. You will need to expose about 8 inches of wire to make the connections to the power buss and multiplexer.

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4. Use a wire stripper to strip a 0.25-inch length at the end of each wire. On the analog soil moisture/soil temperature sensor, there are 7 wires. Red (Power), Black and Yellow are together (Ground), Blue (Voltage 1), Brown (Voltage 2), Green (Voltage 3), White (Voltage 4). There is a silver shield wire along with all the other wires, simply cut this wire off as it is not used. For digital soils, there are just three wires: red (12V power), blue (data), and black (ground).

Wire ends shown for analog (left) and SDI-12 (right)

5. Use duct seal to seal up the bulkhead connector. Mark the end on the conduit with rebar, T-post, or soil marker provided.

Wiring for Analog Soil Moisture/Soil Temperature Sensors at sites without separate Soils NEMA enclosure

Soil power buss strip for analog soil sensors Multiplexer for analog soil sensors

1. The Blue, Brown, Green, White sensor wires are connected to the multiplexer as shown.

2. Replacement soil sensor are wired in the same sequence and position as the sensor being replaced. It is best to work sequentially to minimize the chance of error.

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Wiring for Digital SDI-12 Soil Moisture/Soil Temperature Sensors at sites without separate Soils NEMA enclosure Most SCAN sites have digital SDI-12 soil moisture/soil temperature sensors. These sensors have three wires - Red = power, Black = ground, and Blue = signal. The Red, Black, and Blue wires are connected to a buss strip for each sensor depth.

Inside NEMA enclosure with soils buss strip on the lower right

1. Strip back the black sheath from the cable bundle to expose the individual wires, after cutting the cable for length. Make sure you attach a label to identify each sensor as to the depth it will be placed. Record the serial number(s) in Survey123, if you haven’t done so yet.

2. The digital sensors are programed for a specific depth, so make sure you use the correct sensor for the target depth.

a. If SDI-12 sensors are not pre-programmed:

Program the SDI-12 Hydraprobes through a datalogger using terminal emulator or Stevens’ SDI-12 Xplorer. Digital HydraProbe SDI-12 sensors have to be programed with an ID number that corresponds to a specific depth. The ID convention is 1, 2, 3, 4, or 5, which corresponds to 2, 4, 8, 20, and 40” depths, respectively. The data reporting sequence also has to be programmed as well: ABCDF. This will ensure that the data line up properly with the program and database. It is strongly recommended to write the depth with a sharpie on the body of the probe as soon as it is programmed and affix a label on the lead-end identifying the depth. Record serial numbers in Survey 123.

3. Steps to program SDI-12 probes using Terminal Emulator in Loggernet

a. Connect to data logger using Loggernet

b. Click on Datalogger menu at top of Connect screen and choose Terminal Emulator

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c. Click Open Terminal at bottom of screen and hit enter twice

d. Type “SDI12”

e. Select control port that is being used for the single sensor you are programming

f. To program sensor #1 (2” sensor) - type “1xm!” (For sensor #2, you would type “2xm!”, etc)

g. To program the correct communication protocol, type “1xm=ABCDF” (For sensor #2 it would be “2xm=ABCDF”, etc)

h. To make sure it is programmed correctly, type “1!” and you should see “ABCDF” returned as a result

Station Battery WARNING: BE EXTREMELY CAUTIOUS WHEN WORKING ON THE BATTERIES, AS THEY CAN CAUSE SEVERE

BURNS, DESTROY THE DATA LOGGER, COMMUNICATION DEVICE, AND ATTACHED SENSORS.

IMPORTANT: Wear gloves and use tools with insulated handles whenever disconnecting or connecting batteries.

There are several sizes of batteries and many of the stations might have two batteries in the lower NEMA enclosure or on the floor of the stations with a building. Newer stations typically have one battery.

1. When disconnecting a battery, disconnect the ground (negative) side first, then the positive side.

2. When connecting a battery, connect the positive side first, then the ground (negative) side. This is done to help prevent damage to the electronics.

3. Check the batteries for corrosion – if corrosion is present, use battery cleaner and a brush to clean terminals.

4. Clean the battery terminals with a small brass or metal brush and Battery Cleaner, spray that on the terminal and connector wire. You might need to scrape the ring connector to clean it with a file or brush.

5. Remove the connector from the battery to make sure you get it clean.

6. Once the wire connector and battery terminal are clean, reattach the wire connector to the battery.

7. Brush on Terminal Battery Protector or dielectric grease, to the terminal and wire connector.

8. Tighten the lugs back down on the battery and secure the wires.

Battery installation If a new battery is required:

1. Disconnect the power cable to the data logger and the cell modem or radio before working on the batteries.

2. After the power to the data logger and communications device are unplugged, using an insulated adjustable wrench remove the negative (black) wire first remove the wire connected to the positive (red) post and put a piece of electrical tape on the connector to ensure it doesn’t contact ground.

3. If the station has two batteries, some of these will be stacked together in the lower NEMA, whereas others might be on the floor. They are always wired in parallel as shown in the photos.

4. If the station has a building:

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a. Remove the top negative black wire first.

b. Remove the wires connected to the negative post which can be red or white, and put a piece of electrical tape on the connector to ensure it doesn’t contact ground.

5. Remove the black wire from the remaining battery and move the connecting wire away from the lower box.

6. Disconnect the remaining red wire and remove the second battery.

7. Replace old batteries with new batteries

8. Connect red battery connector wire between positive battery terminal and 12v power bus.

9. Connect black battery connector wire between negative battery terminal and ground bus

10. Tighten the lugs on the batteries.

11. Brush on Terminal Battery Protector or dielectric grease to the terminals.

12. Check all wiring connections.

13. Remove used batteries from site – recycle at approved disposal facility.

Battery system on the floor

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Battery system that is stacked on top of each other in lower NEMA Station with one battery

Wiring diagram (See Appendix C).

Power connector for data logger: Red and Black wires attached to green plug

Battery + Red Data logger

Battery - Black Data logger

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Internal Relative Humidity Sensor This sensor is located inside the large NEMA enclosure which has the data logger and communication device.

It is used to check to see if the desiccant needs replacement.

Internal Relative Humidity sensor (circled in red)

The Internal RH sensor has the white tip attached to the black cable and is held into place by a plastic white clamp on the right had side of photo.

If this sensor needs replacement (See Appendix C):

1. Unplug the data logger power cable.

2. Identify the three wires for this sensor and confirm them with the wiring diagram.

3. Disconnect the three wires and connect the new sensor.

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Station Grounding IMPORTANT: Proper grounding of the station is imperative. The quality of the data depends on how well the station is grounded.

Typically, SCAN stations will have one ground wire attached to the three legs of the antenna tower and uses hose clamps to secure the bare copper wire.

There is an 8-foot ground rod driven into the ground and the wires are attached to this ground rod. One ground wire is attached to the bottom of the large (Upper) enclosure and services as the station ground.

1. Ensure all the ground wires are attached and secure.

2. Inside the large NEMA box is usually a green wire running from the ground connector to the data logger. Ensure that this wire is in place and secure.

3. Correct and tighten any loose connections.

4. If replacing/moving ground rod, it is very important to make sure that it is at least 10 feet from the soil sensors.

Solar Panel Regulator There are two types of solar panel regulators used in SCAN. The older JL-2 regulators are being replaced with Morningstar SunSaver 10 regulators. If the JL-2 is bad, you will replace them with the new SunSaver 10.

JL-2 regulators SunSaver 10 regulator

Many of the stations that have this type of regulator have two JL-2 regulators.

1. Before replacing any of the regulators, unplug the data logger and communication device.

2. Remove all the wires going to the power buss (left side of photo).

3. Unscrew the JL-2 regulators and remove.

Mount the new SunSaver 10 regulator with ½ inch long self tapping screws. You will generally only be able to use one mounting screw.

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1. There are two terminals that are clearly marked on the SunSaver regulator (by a sun icon) where the solar panel is to be connected to the regulator. The Battery connections are the next two positions.

2. Attach the two wires from the solar panel to the solar panel terminals on the regulator.

3. Attach power wires that connect the battery terminals to the 12V power and ground bus, which will be connected to the site battery.

NOTE: The three light indicators on the regulator will indicate if the battery is being charged with the Red, Yellow, or Green indicator LED lights.

4. The solar panel regulator will indicate if you have the wires connected in the wrong place. Switch the positive and negative wires if they are incorrect.

Cellular Modem

Currently most of the SCAN stations use cellular modems.

Cell modem replacement To replace an RV50(X) modem:

1. Unplug the power, coax, and logger cables and remove modem from backplate using a screwdriver.

2. With the new modem, plug the power cord in.

3. Connect coax cable to cellular coax connection port (circled in photo).

IMPORTANT: Be very careful as this connection is fragile, do not use a wrench (hand tighten only!).

4. Attach the new RV50 modem to the mount using with ½ inch long self tapping screws.

5. Connect the Serial Cable to the RV50. Plug in the power cable to the modem (next to the antenna cable). The red light on the modem should light up immediately. If it doesn’t, check the fuse and make sure the battery is connected correctly.

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6. The modem lights will blink on and off during the activation cycle. After a few minutes, the Network and Signal lights should stop blinking and turn off (only the green Power light will remain on).

7. Take a photo of the cardboard box that shows modem information and a photo of the modem in the enclosure.

8. When the blinking stops, call the NWCC and verify they can connect to the cell modem and data logger.

IMPORTANT: Schedule this check-in prior to site visit so NWCC staff is prepared to assist.

Wiring for RV50 cell modem

Cell Modem Red Power 12V White Power 12V Black Ground Green NOT USED

RV-50 modem and mounting bracket

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RV-50 front

Cellular Antenna Most SCAN stations have a small white antenna mounted on the tower.

Cellular Antenna replacement

1. Before replacing antenna, unplug power to cell modem.

2. Use a ladder or tower climbing equipment to safely access the antenna location.

3. With pliers, gently remove coaxial cable from the bottom of the antenna.

4. Detach antenna from mount and replace with new antenna.

5. Reattach coaxial connection. Antenna should face upward.

6. When replacement is complete, plug power back into modem and wait 5-10 minutes for activation to occur. Network and signal lights should stop blinking.

7. When the blinking stops, call the NWCC and see if they can connect to the cell modem and data logger.

IMPORTANT: Schedule this check-in prior to site visit so NWCC staff is prepared to assist.

Connecting and Programming the Data Logger

1. Connect the green power connector on the data logger to the 12V power bus and ground bus using red and black wires. Plug the power cable into the data logger.

Connect antenna cable (coax) to the appropriate spot.

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2. Connect to the CR1000(X) datalogger via Loggerlink app on cell phone using the IP address of the modem.

3. Important! Set the date and time of the datalogger to the current standard time for the local time zone. Do not use daylight savings time – use standard time.

4. Send the standard SCAN datalogger program to the datalogger using Loggerlink or Loggernet.

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Appendix A: Example Site Inventory

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Appendix B: Survey 123 Manual

User Guide

Survey123 SCAN “public form”

Updated: 3/18/2021

Beginning in Spring, 2021, the SCAN network is adopting “Survey123” for all field note and inventory tracking.

Survey123 is an ESRI application that can be used on iPhone, Android, and PC that allows users to enter site visit data into a predefined form. The following guide describes how to setup and collect SCAN site visit and Inventory information.

1. Setting up Survey123 for field data collection

a. Sign up for an NRCS ESRI online Account

To use the Survey123 mobile application, you must have an “ArcGIS Online” account and be added to the “SCAN Maintenance” group on ArcGIS Online. To request an account and access to the “SCAN Maintenance” group, fill out the relevant information in this google spreadsheet (ArcGIS Online Account Request). Dave Eiriksson (david.eiriksson@usda.gov) monitors activity in this spreadsheet and will create accounts and grant access to the group as requested. After your account is created, you will receive an automatically generated email from ESRI prompting you to set up a password to activate your account. TIP: You will regularly have to enter this password, so pick one that is both memorable and strong.

b. Download the Survey123 App

If you plan to use Survey123 on an iPhone, Android, or tablet, download the Survey123 App from the App store supported by your device. If you want to use Survey123 on your government laptop, the application can be downloaded from the Software Center.