Rosemount 3100 Series Ultrasonic Level Transmitter
The Rosemount 3100 Series is a top-mounted ultrasonic level transmitter designed for continuous monitoring of liquid levels in tanks, vessels, wet wells, and open channels. The device emits ultrasonic pulses from the sensor face toward the liquid surface. The reflected echo is detected by the transmitter, and the internal electronics calculate the time delay between transmission and reception. This time of flight measurement is converted into distance and then into level based on configured tank geometry.
The series includes:
Rosemount 3101 (basic level measurement)
Rosemount 3102 (advanced level, volume, flow)
Rosemount 3105 (hazardous area applications)
Technical Specifications
| Parameter | Specification |
|---|---|
| Measurement Principle | Ultrasonic Time-of-Flight |
| Measurement Type | Continuous non-contact level |
| Output Signal | 4–20 mA |
| Communication | HART (3102 / 3105) |
| Range (3101) | ~0.3 to 8 m |
| Range (3102 / 3105) | ~0.3 to 11 m |
| Accuracy | Up to ±0.25% of measured distance (model dependent) |
| Resolution | ~1 mm |
| Blanking Distance | ~0.3 m |
| Power | 2-wire loop powered |
| Display | Integrated LCD |
| Housing | Industrial polymer or metal options |
| Wetted Material | PVDF (sensor face) |
| Operating Temp | approx. -30°C to +70°C |
| Protection | Industrial / hazardous variants available |
What Was the Rosemount 3100 Series Ultrasonic Level Transmitter Used For?
The Rosemount 3100 Series was primarily installed to monitor liquid levels in tanks and open environments without physical contact with the process fluid. It was widely used in:
- Water and wastewater treatment plants
- Chemical storage tanks
- Pumping stations and lift stations
- Industrial process vessels
- Reservoirs, sumps, and basins
- Open channel flow systems (with weirs and flumes)
Product Lifecycle Status
The Rosemount 3100 Series is classified as a retired / obsolete product family.
Key implications:
- No longer recommended for new installations
- Limited availability of spare parts
- Legacy systems still in operation globally
- Replacement strategy required for modernization projects
Recommended Replacement
The Rosemount 3100 Series Ultrasonic Level Transmitter does not have a single universal drop-in replacement because selection depends on the specific application, but in most modernization projects it is typically replaced with modern Rosemount non-contacting radar level transmitters such as
- Rosemount 1208A for standard water and wastewater applications
- Rosemount 5408 for more complex or demanding industrial processes.
These radar-based technologies are preferred over legacy ultrasonic systems because they provide higher measurement stability, improved accuracy, and better performance in challenging conditions such as vapor, foam, and temperature fluctuations, while also offering advanced diagnostics, reduced maintenance requirements, and long-term product lifecycle support suitable for modern industrial automation systems.
Need Support for Replacement or Upgrade?
Many maintenance and procurement teams contact us when dealing with urgent operational issues involving retired or discontinued instrumentation, including:
- Difficulty sourcing legacy Rosemount or Bently Nevada products
- Missing or incomplete technical documentation (manuals, datasheets, wiring details)
- Unexpected equipment failures affecting plant operation
- Vibration or level measurement issues impacting production efficiency
- Emergency shutdown situations requiring immediate replacement support
- Urgent need for obsolete part identification or cross-referencing
In such cases, we assist by analyzing available part numbers or application details to quickly identify practical repair, replacement, or upgrade solutions to minimize downtime.
