Ultrasonic flow transmitters are essential instruments in industries ranging from oil and gas to water treatment and chemical processing. These devices offer non-intrusive, maintenance-free, and highly accurate flow measurement solutions for a variety of fluids. However, understanding and interpreting the datasheet of an ultrasonic flow transmitter can be daunting, especially for engineers and technicians who are new to the field.
This blog aims to demystify the elements of an ultrasonic flow transmitter datasheet by breaking it down section by section. By the end of this 2000-word guide, you will be equipped to decode any ultrasonic flow transmitter datasheet with confidence.
Table of Contents
- What Is an Ultrasonic Flow Transmitter?
- Purpose of the Datasheet
- Key Sections of the Datasheet
- General Specifications
- Flow Measurement Technology
- Process Conditions
- Physical and Mechanical Data
- Electrical Specifications
- Output and Communication Protocols
- Installation Requirements
- Certifications and Approvals
- Ordering Information
- Common Terminologies Explained
- Sample Datasheet Analysis
- Tips for Engineers
- Conclusion
- What Is an Ultrasonic Flow Transmitter?
An ultrasonic flow transmitter measures the flow of liquids (and sometimes gases) using sound waves. There are two main types:
- Transit Time Type – Best for clean fluids; measures the time difference between upstream and downstream ultrasonic signals.
- Doppler Type – Suited for dirty or aerated fluids; relies on frequency shift caused by particles or bubbles in the fluid.
Unlike mechanical flowmeters, ultrasonic meters are non-intrusive, offering minimal pressure drop and high longevity.
- Purpose of the Datasheet
An instrument datasheet serves as a technical blueprint. It provides:
- Device capabilities and limitations
- Environmental and process suitability
- Design specifications for integration
- Reference for selection, procurement, and maintenance
- Key Sections of the Datasheet
Let’s walk through the critical parts of a typical ultrasonic flow transmitter datasheet.
- General Specifications
This section gives an overview of the model, including:
- Model Number/Series
- Manufacturer
- Measurement Principle: Transit Time or Doppler
- Typical Applications: Water, chemicals, hydrocarbons, etc.
Example:
| Parameter | Description |
| Model | UF-2000 |
| Measurement Type | Transit Time |
| Pipe Sizes | DN15 to DN1200 |
| Fluid Types | Clean liquids |
Engineering Insight: Confirm the technology type aligns with your application (e.g., transit time won’t work with slurries).
- Flow Measurement Technology
This section describes how the flow is measured.
- Measuring Range (Min & Max flow rates or velocity)
- Turn-down Ratio (e.g., 100:1)
- Accuracy (±1% of reading, or better)
- Repeatability (±0.2%)
Example:
| Parameter | Value |
| Velocity Range | 0.03 to 12 m/s |
| Accuracy | ±0.5% of reading |
| Repeatability | ±0.2% |
| Turn-down Ratio | 100:1 |
Engineering Insight: A high turn-down ratio allows wide flow variations without sacrificing accuracy.
- Process Conditions
These specify the limits within which the transmitter can operate.
- Fluid Temperature Range (e.g., -40 to 150°C)
- Pressure Rating (e.g., 16 bar, ANSI 150)
- Viscosity Range (for Doppler types)
- Pipe Material Compatibility
Example:
| Parameter | Specification |
| Temperature Range | -20°C to +120°C |
| Pressure Range | Up to 40 bar |
| Pipe Materials | Steel, PVC, HDPE |
Engineering Insight: Ensure the pipe material and temperature range match your process.
- Physical and Mechanical Data
Covers construction details and dimensional drawings:
- Sensor Type (Clamp-on, In-line, Insertion)
- Sensor Housing Material (e.g., Stainless Steel, Aluminum)
- Ingress Protection (e.g., IP66, IP68)
- Weight and Dimensions
Example:
| Sensor Type | Clamp-on |
| Material | Stainless Steel 316 |
| Enclosure Rating | IP68 |
| Dimensions | 120 x 80 x 70 mm |
Engineering Insight: Clamp-on sensors are ideal for retrofit projects due to non-intrusiveness.
- Electrical Specifications
Defines the power and wiring details:
- Power Supply Requirements (e.g., 24 VDC, 230 VAC)
- Power Consumption (e.g., <5W)
- Terminal Layout or Connector Type
- Cable Entry Sizes
Example:
| Supply Voltage | 24 VDC |
| Power Consumption | 3W |
| Cable Entry | M20 gland |
| Isolation | Galvanic |
Engineering Insight: Ensure compatibility with existing power supplies and junction boxes.
- Output and Communication Protocols
Crucial for data integration with DCS, PLC, or SCADA.
- Analog Output: 4-20 mA (typically scaled to flow range)
- Pulse Output: For totalized flow
- Digital Communication: HART, Modbus, Profibus, Foundation Fieldbus
- Alarm Relays
Example:
| Analog Output | 4-20 mA, isolated |
| Digital Output | Modbus RTU over RS-485 |
| Pulse Output | Open collector, max 1kHz |
| Relay Output | 2 relays, SPDT, 2A@250VAC |
Engineering Insight: For smart integration, go for digital protocols that allow diagnostics and remote calibration.
- Installation Requirements
Installation guidelines are often included or referenced.
- Straight Run Requirements (e.g., 10D upstream, 5D downstream)
- Sensor Mounting Orientation
- Pipe Surface Preparation
- Coupling Grease Specification (for clamp-on)
Engineering Insight: Improper installation can degrade accuracy. Always follow straight pipe requirements.
- Certifications and Approvals
Ensures compliance with international safety and performance standards:
- ATEX, IECEx – For hazardous area use
- UL, CSA – North American electrical standards
- CE, RoHS – European compliance
- NEMA/Ingress Protection
Example:
| ATEX Rating | II 2G Ex db IIC T6 Gb |
| IP Rating | IP68 |
| CE Mark | Yes |
Engineering Insight: Use certified instruments in hazardous zones to avoid legal and safety issues.
- Ordering Information
Most datasheets include a model code for ordering:
Example Code: UF2000-TT-C1-A1-P1-F2
Where:
- TT = Transit Time
- C1 = Clamp-on sensor
- A1 = 4-20 mA output
- P1 = Pulse output
- F2 = Modbus RTU
Engineering Insight: Always use the ordering code breakdown to verify the model being supplied matches your needs.
- Common Terminologies Explained
- Transit Time vs Doppler: Time-based for clean fluids vs. frequency-shift-based for dirty fluids.
- Turn-down Ratio: Ratio between maximum and minimum measurable flow.
- Clamp-on: Sensor mounted externally on pipe; non-invasive.
- Pulse Output: Sends pulses corresponding to volume; used for batching.
- Ingress Protection (IP): Dust and water resistance rating.
- Sample Datasheet Analysis
Let’s consider a sample extract and interpret key elements:
| Parameter | Value |
| Model | UF-4000 |
| Measurement Type | Doppler |
| Pipe Size | DN50 to DN2000 |
| Accuracy | ±2% of reading |
| Outputs | 4-20 mA, Pulse, Modbus RTU |
| IP Rating | IP67 |
| Power Supply | 24 VDC |
| Fluid Temperature | -10°C to 80°C |
Interpretation:
- Suitable for large dirty fluid lines (e.g., wastewater)
- Needs 24 VDC supply, so ensure compatible wiring
- Non-intrusive clamp-on mounting makes it ideal for retrofits
- Not suitable for high-temperature applications (>80°C)
- Tips for Engineers
- Always cross-check operating conditions (temp, pressure, fluid type) with datasheet limits.
- Avoid undersizing – ensure your max flow is within 80% of transmitter range.
- Check for hazardous area approvals before installation in classified zones.
- Verify integration capabilities – 4-20 mA is standard, but diagnostics need HART or Modbus.
- Use the ordering code – this is your reference during procurement.
- Conclusion
An ultrasonic flow transmitter datasheet is more than just a collection of specifications – it’s a powerful document that helps you ensure proper selection, integration, and performance of the instrument in your system. By understanding each section – from flow range to output types and certifications – you can make informed decisions that impact efficiency, reliability, and safety in your plant.
Whether you’re a design engineer, commissioning specialist, or maintenance technician, this guide equips you to read between the lines and confidently decode any ultrasonic flow transmitter datasheet.