Ultrasonic Level Transmitter Installation Checklist

An ultrasonic level sensor must be properly installed in industrial and commercial applications to provide accurate consistent readings. 

A organized method assures that the sensor performs efficiently, minimizes errors, and reduces the possibility of failure. 

A complete installation checklist is provided below, which includes key steps, safety and environmental considerations, as well as compliance with standards and regulations.

How to install an ultrasonic level transmitter?

Step 1: Pre-Installation Preparations

Select the Right Sensor

• Ensure the selected sensor has a sensing range greater than the actual distance to the target. 
• Consider for factors such as sensing distance, blanking distance (the area where detection is not possible), and target material (soft or hard).
• Sensors designed for longer distances or certain target materials may perform better in specific environments.
• Ensure that the sensor complies with relevant standards, such as IEC 61508 (Functional Safety) for critical systems.

Use a Clean Power Source

• Ultrasonic sensors are sensitive to electrical noise. It is crucial to use a stable, high-quality power supply to avoid interference that can affect sensor performance. 
• Poor-quality sources could introduce noise, causing erroneous readings or system failure.
• Refer to IEC 61000-4 (Electromagnetic Compatibility) for guidance on managing electrical noise.

Review Manufacturer’s Manual

• Study the manufacturer’s installation guide and datasheets to understand the specific mounting, electrical, and calibration requirements for your sensor. 
• Pay close attention to any limitations or recommendations based on your sensor model.

Reference P&ID, Hookup, Wiring, Loop Diagrams, and Datasheets

• Before installation, ensure all relevant documentation such as P&ID (Piping and Instrumentation Diagram), instrument hookup drawings, wiring diagrams, Instrument loop diagrams, and Instrument datasheets are reviewed. 
• These documents provide essential information about the Transmitter’s placement, electrical connections, and integration with the control system, ensuring compatibility and correct installation procedures.
• Proper referencing of these documents helps avoid installation errors and ensures that the system operates as designed.

Step 2: Safety Considerations

Personal Protective Equipment (PPE)

• Ensure all personnel handling the sensor installation wear appropriate PPE, such as safety glasses, gloves, and protective footwear. This reduces the risk of injury from electrical shock or mechanical hazards.

Lockout/Tagout (LOTO)

• Before starting installation, use LOTO procedures to isolate power sources, ensuring a safe environment during sensor setup.

Hazardous Area Installation

• In classified hazardous areas, select sensors that are certified for use in explosive atmospheres (e.g., ATEX, IECEx certification). 
• Ensure that intrinsically safe barriers or explosion-proof housings are used as per the manufacturer’s specifications.
• Confirm the sensor’s certification for use in explosive atmospheres and install according to the hazardous location classifications.

Step 3: Mounting Location and Orientation

Choose an Optimal Mounting Location

• The sensor must have a clear column of air to the target. A general rule of thumb is a 3-4 foot diameter clearance, depending on the transmitter’s range. 
• Avoid placing it near obstructions such as pipes, beams, or fill spouts, as these could cause reflections or echoes, leading to inaccurate readings.

Avoid Direct Center of Domed Tops

• If mounting inside a domed tank, avoid placing the sensor at the top center. This position can amplify unwanted signals and create false readings.

Keep Away from Tank Walls

• Install the sensor far from tank walls, especially if they are corrugated or prone to product buildup, which can cause false echo readings. 
• Ensure that the ultrasonic signal has an unobstructed path to the liquid or material surface.

Maintain a 90° Mounting Angle

• The sensor face should always be perpendicular (90°) to the target surface for optimal performance. 
• Even slight deviations can result in significant signal loss or inaccurate level measurements.

Bracket Mounting

• Ensure the sensor is mounted on a sturdy, vibration-free bracket. The bracket material must withstand environmental exposure such as high temperatures, chemicals, or corrosive gases. 
• Proper bracket mounting ensures stability, minimizing sensor movement that could lead to inaccurate readings or damage.
• In open environments, install the sensor using a bracket or by drilling a 60mm circular hole in the top of the tank or lid. Secure with the locknut from underneath.

Probe Alignment

• Ensure the transmitter’s probe face is parallel to the liquid surface for accurate measurement.
• During installation, avoid obstructions such as protrusions or edges that may interfere with the waves emitted by the probe.

Shade from Direct Sunlight

• If the sensor is outdoors, protect it from direct sunlight by using shading methods such as a canopy or a protective housing. 
• Prolonged exposure to sunlight can cause overheating, leading to signal degradation or damage to the sensor’s housing.

Step 4: Mechanical Installation

Ensure Proper Blanking Distance

• Install the sensor above the maximum expected liquid level by at least the minimum blanking distance (typically 4-12 inches depending on the model). 
• This ensures accurate measurements without interference from reflections too close to the sensor.

Hand Tighten the Sensor

• Always hand-tighten the sensor when installing it into its mount or fitting to avoid damaging the threads or over-tightening, which can lead to mechanical failure.

Stilling Well (If Necessary)

• In cases where an unobstructed path is not feasible, consider using a stilling well:
  1. Use a seamless PVC or steel pipe with an appropriate NPT fitting.
  2. Drill a ¼” vent hole within the blanking distance for pressure equalization.
  3. Drill additional ¼” holes at the bottom for liquid movement.
  4. Ensure the pipe is vertical and aligned, with the sensor face above the maximum liquid level by the blanking distance.

Step 5: Electrical Installation

Ensure Power is Isolated

• Turn off all power sources before connecting the sensor to avoid electrical shock or damage to the equipment.

Proper Grounding

• Ground the sensor and transmitter according to manufacturer guidelines to reduce electrical noise and ensure operator safety. 
• Faulty grounding can lead to noise issues and affect sensor accuracy.

Cable Glands and Seals

• Use appropriate cable glands and seals to maintain ingress protection (IP) ratings, especially in environments prone to moisture or dust. 
• Check that the glands and seals are secure to prevent environmental ingress, which could damage the sensor.

Connect the Cable(s) to the Transmitter

• Follow the wiring diagram for correct cable connections between the sensor and the transmitter. 
• Be mindful of power, communication, and signal cables to ensure proper operation. 
• For specific connections (e.g., 4-20 mA, HART, Modbus), adhere to the manufacturer’s recommended guidelines.
• Avoiding crossed wiring or shorts that could lead to equipment failure and check the connections for any loose wiring or exposed cables to maintain signal integrity.

Avoid High-Voltage Lines

• Route signal cables away from high-voltage power lines or other sources of electromagnetic interference (EMI). Signal integrity can be compromised if interference is present.

Click here for Ultrasonic Level Transmitter Working Principle

Step 6: Sensor Configuration and Calibration

Calibrate the Sensor

• Follow the manufacturer’s calibration procedure to adjust the sensor to your tank dimensions and measurement range. This process is crucial to ensure the sensor provides accurate readings.

Configure Output Signals

• Set the output signals (e.g., 4-20 mA, relay output) based on the system’s requirements. Ensure that communication interfaces like HART or Modbus are properly configured and tested.

Blind Zone

• The blind zone is the area immediately below the sensor where accurate measurements cannot be taken due to the proximity of the emitted waves to the sensor. Each ultrasonic sensor has a specific blind zone, often given in the sensor’s datasheet (e.g., 0.45 meters).

Minimum Measurable Level

• The minimum measurable level is determined by the blind zone. The distance between the highest liquid level and the probe must always be greater than the blind zone. If the blind zone is 0.45 meters, the liquid must not come closer than 0.45 meters to the sensor.
• For Example: If the blind zone is 0.45 meters, the highest measurable liquid level must be at least 0.45 meters below the sensor. Anything above this point is within the blind zone and cannot be measured accurately.

Maximum Measurable Level

• The maximum measurable level is determined by the sensor’s range. The installed height (TH) should be less than or equal to the sensor’s maximum range.
• For Example: If the sensor has a range of 6 meters, the actual maximum measurable liquid level will be 6 meters – 0.45 meters (blind zone) = 5.55 meters.

Transmitter Base Units

• If your ultrasonic sensor system uses a separate transmitter base unit, install and configure it as per the manufacturer’s guidelines. 
• Ensure that it is appropriately calibrated and connected to the sensor, control system, or SCADA for seamless communication and data transfer.

Step 7: Functional Testing and Verification

Power On and Test

• Once installation is complete, power the system and compare the sensor readings with manual measurements. Ensure that the Transmitter responds accurately across its operational range.

Simulate Various Levels

• If possible, simulate different levels of liquid in the tank to verify that the sensor’s response is consistent across the expected range.

Inspect and Document

• Double check all mechanical and electrical connections. 
• Ensure all entry points are properly sealed, and document the sensor’s configuration settings for future reference.

Step 8: Environmental Considerations

Hazardous Area Environmental Factors

• Consider hazardous environmental factors like moisture, dust, or corrosive gases in explosive atmospheres. 
• Install proper sealing, cable glands, and explosion-proof or intrinsically safe components where required. 
• This ensures compliance with safety regulations such as IEC 60079 for explosive atmospheres.

Temperature and Humidity

• Consider the environmental conditions in which the sensor will operate. If the area experiences extreme temperature variations, choose a sensor designed to handle these conditions. 
• Moisture and condensation can affect sensor performance, so ensure proper sealing.

Chemical Exposure

• If the sensor will be exposed to aggressive chemicals or vapors, choose one with a chemically resistant housing or add protective coatings to prevent degradation.

Step 9: Maintenance Planning

Regular Inspection

• Schedule regular inspections to check for physical damage, dirt, or debris on the sensor face that could interfere with readings. 
• Clean the sensor as required and recalibrate periodically to maintain accuracy.

Click here for Understanding the Factors Influencing the Accuracy of Ultrasonic Level Measurement

Step 9: Compliance with Standards and Regulations

Ensure the installation complies with relevant industry standards and regulations for the ultrasonic level sensors, including:

• IEC 61508 for Functional Safety.
• IEC 60079 and ATEX for explosive atmospheres.
• IEC 61000-4 for Electromagnetic Compatibility (EMC) compliance.
• IECEx certification for hazardous location installations.

Click here for more Essential Instrumentation Checklists

Ultrasonic Level Sensor Installation Excel Checklist for download

The Ultrasonic Level Sensor Installation Checklist is designed to ensure a structured and efficient installation process, minimizing potential errors and ensuring accurate measurements. 

This checklist covers all essential steps, from pre-installation preparation to sensor calibration and functional testing. It includes safety precautions, mounting location guidelines, and environmental considerations, ensuring compliance with industry standards and optimal performance.

Use this checklist to facilitate smooth installation, extend sensor longevity, and maintain reliable readings in various industrial and commercial applications.

To obtain a downloadable template for the Ultrasonic Level Sensor Installation checklist, please follow the link below.

For more Engineering documentation templates – click on Downloadable Engineering Documentation Instrumentation and Control Templates

For more Instrumentation calibration templates – click on Downloadable Instrumentation Calibration Report Preparation Templates

FAQ on Ultrasonic Level Transmitter Installation Checklist

What is the accuracy of an ultrasonic level transmitter?

The accuracy of an ultrasonic level transmitter typically ranges from ±0.25% to ±0.5% of the full scale. The exact accuracy depends on the model, manufacturer, and the specific conditions of the installation​.

What is the range of an ultrasonic transmitter?

The range of an ultrasonic transmitter can vary, but typically it is designed to measure distances from a few centimeters up to 30 meters (approximately 100 feet). The range depends on the model and the application, with some models capable of measuring smaller distances and others optimized for longer-range measurements

What is the frequency of an ultrasonic level transmitter?

The frequency of ultrasonic level transmitters generally falls between 20 kHz and 200 kHz. Higher frequencies are used for short-range measurements, while lower frequencies are better suited for longer ranges