Siemens Radar level transmitters / SITRANS LR560

7ML54400DA000AC2-Z (for general solids applications)

The SITRANS LR560 is a high-frequency (78 GHz) FMCW (Frequency Modulated Continuous Wave) radar level transmitter that measures the level of solids in silos by emitting a radar beam from its lens antenna, which reflects off the material's surface. The device measures the time-of-flight and frequency shift of the reflected signal to calculate the material's distance and thus its level. Its design, using a narrow beam and Process Intelligence, allows for accurate non-contact measurement, even in harsh conditions with extreme dust, high temperatures, and potential product buildup

Here's a step-by-step breakdown of its working principle

1. Signal Transmission: The SITRANS LR560's lens antenna transmits a high-frequency (78 GHz) microwave signal downwards into the silo or vessel.
2. Reflection from Material: This radar signal reflects off the surface of the solid material in the silo.
3. Signal Reception: The reflected signal travels back to the transmitter's antenna.
4. Frequency Shift (Doppler Effect): Because the material is a different distance from the transmitter, the frequency of the reflected signal is slightly different from the transmitted signal. This frequency difference, due to the Doppler effect, is directly proportional to the distance to the material.
5. Time-of-Flight Calculation: The electronic circuit of the device processes the signal to determine the time it took for the signal to travel to the material and return.
6. Level Calculation: Based on the time-of-flight and the known speed of the radar waves, the device calculates the precise distance to the material.
7. Continuous Level Monitoring: This process is repeated continuously, providing a continuous level measurement of the solid material in the silo

Key features contributing to its effectiveness:

• High Frequency (78 GHz): This provides a very narrow beam, minimizing interference from vessel walls and resulting in optimal reflection from sloped surfaces in silos.
• Lens Antenna: The lens design is highly resistant to product buildup, ensuring a clear path for the signal.
• Process Intelligence: Advanced echo processing ensures reliable performance, even in challenging conditions with extreme dust or condensation.
• Non-Contact Measurement: The measurement is done from a distance without physical contact, preventing wear and tear on the instrument

 Full Datasheet

Transmitter & Antenna Feature  

• Manufacturer :  Siemens
• Product No. : 7ML54400DA000AC2-Z
• SITRANS LR560 Radar level tr ansmitt er with flush lens antenna:  7ML5440 - non-contact, 100 m (328 ft) range
• Measurement and process temperature range: 0 - 40 m (131 ft) max range, ‑40 ... +100 °C
• Process connection: D -  80 mm/3 inch, 316L stainless steel
• Enclosure (with cable inlet): A - Stainless steel, 1 x ½" NPT
• special: 0 - none
• special: 0 - none
• Pressure rating: 0 - 0.5 bar g (7.5 psi g) maximum
• Output/communication: A - 4 ... 20 mA, HART
• Approvals:  C  - ATEX II 3G Ex nA/nL, 1D, ½D, 2D Ex ta, INMETRO, CE, RED, RCM
• Local display interface:  2  - With
• PROCESS CONNECTION:  1  - 2" NPT (Sch. 40 maximum)
• Special order:  Z  - C11 - Manufacturer's test certificate: M to DIN 55350, Part 18 and to ISO 9000

There are several Model of pressure transmitters, for more details read the PDF below 

Basic Ordering Information Transmitter

3 bar g (40 psi g) maximum

ABM Temperature -40°C to 80°C