Magnetrol Eclipse 706 GWR - Guided Radar Level Transmitter 706-511A-310 +

7AS-1100-A2N-20-061

The Magnetrol 706 Guided Wave Radar (GWR) transmitter works on the principle of Time Domain Reflectometry (TDR), sending electromagnetic pulses down a probe and measuring the time it takes for a reflected pulse from the liquid surface to return. The time delay is converted into a precise distance, providing an accurate liquid level measurement. The technology is also capable of sensing the interface between two liquids of differing dielectric constants, such as oil and water

Here's a breakdown of the principle:

1. Pulse Transmission: The Model 706 generates a pulse of electromagnetic energy that travels down the GWR probe, which acts as a transmission line.  
2. Reflection: When this pulse reaches the surface of a liquid (or a solid), a portion of the pulse is reflected back up the probe. The amount of reflection depends on the dielectric constant of the material at the surface.
3. Time Measurement: The device's high-speed circuitry precisely measures the time it takes for the pulse to travel from the transmitter to the liquid surface and back.
4. Level Calculation: This measured transit time is then converted into a distance, providing the liquid level reading.
5. Interface Measurement: For applications with two liquids, like oil over water, a portion of the pulse continues past the low-dielectric oil and is reflected again by the higher-dielectric water layer, allowing the transmitter to sense the interface between them.
6. High Sensitivity: The Model 706 incorporates advanced circuitry to reduce noise and enhance signal-to-noise ratio, which improves its ability to detect signals even from very low dielectric media or under turbulent conditions.

Small Coaxial Probe

The Magnetrol 7AS probe (found on the Eclipse® 706 GWR transmitter) works on the principle of Time Domain Reflectometry (TDR), also known as Guided Wave Radar (GWR). Electromagnetic pulses are sent down the probe, and a reflection occurs when the pulse encounters the surface of the liquid. An internal high-speed timing circuit measures the time it takes for the pulse to travel to the liquid surface and back, which is then converted into an accurate liquid level reading.

How it Works (Step-by-Step):

1. Pulse Generation: The GWR transmitter generates a short pulse of electromagnetic energy.
2. Pulse Transmission: This pulse travels down the probe (or waveguide).
3. Reflection: When the pulse reaches the surface of a liquid with a different dielectric constant than the surrounding vapor (or air), a portion of the pulse is reflected.
4. Transit Time Measurement: A high-speed timing circuit within the transmitter precisely measures the time it takes for the pulse to travel from the transmitter to the liquid surface and back.
5. Level Calculation: The measured transit time is converted into a distance, providing an accurate liquid level reading displayed on the transmitter.

Key Aspects:

• Guided Wave Radar (GWR): The probe is essentially the "waveguide" for the electromagnetic pulses, guiding them to and from the liquid surface.
• Time Domain Reflectometry (TDR): This is the underlying technology, relying on the time it takes for a pulse to reflect off a change in medium.
• Dielectric Constant: The reflection occurs because the liquid has a higher dielectric constant than the air or vapor above it, which the electromagnetic pulse can detect.
  High-Speed Circuitry: Ultra-high-speed timing circuitry is essential for accurately measuring the short transit times of the pulses.

 Full Datasheet Devices

Transmitter Feature  

• Manufacturer :  Magnetrol 
• Product No. : 706-511A-310
• Model : Eclipse 706 
• BASIC MODEL NUMBER: 706 -  ECLIPSE 4th Generation Guided Wave Radar (GWR) Level Transmitter
• POWER: 5 - 24 VDC, Two-Wire 
• SIGNAL OUTPUT : 1 -  4–20 mA with HART
• SAFETY OPTIONS: 1 - Special
• ACCESSORIES/MOUNTING: A -Digital Display and Keypad - Integral
• CLASSIFICATION: 3 - Explosion-proof (FM & CSA CL 1 Div 1, Grps B, C, D)
• HOUSING: 1 - Die-cast Aluminum, Dual-compartment, 45-degree
• CONDUIT CONNECTION:  0  - 1/2" NPT

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

Basic Ordering Information Transmitter

Probe Feature  

• Manufacturer :  Magnetrol 
• Product No. : 7AS-1100-A2N-20-061
• TECHNOLOGY : 7  - ECLIPSE GWR Probes - Model 706
• MEASUREMENT SYSTEM: A - English
• CONFIGURATION/STYLE (RIGID): S - Small Coaxial, Saturated Steam (+300 °C/+345 °C [+575 °F/+650 °F]), Max. Length=610 cm (240”) — Only available with 10th digit N, 9th digit 2 or 3
• PROCESS CONNECTION – SIZE/TYPE: 11 - 3/4" NPT Thread – Not available with 3rd Digit D
• CONSTRUCTION CODES: 0 - Industrial
• FLANGE OPTIONS: 0 -  none
• MATERIAL OF CONSTRUCTION - FLANGE/NUT/ROD/INSULATION: A -  316 SS
• SPACER MATERIAL: 2 -  PEEK HT — Only available with 3rd digit D — ε_r ≥ 1.4 (+345 °C/+650 °F) or S (+300 °C/+575 °F)
• O-RING MATERIALS/SEAL OPTIONS: N -  None/Glass Ceramic Alloy — Available only with 3rd digit D, P or S
• PROBE SIZE/ELEMENT TYPE/FLUSHING CONNECTION: 2 -  Small Coaxial (22 mm/0.875 inches)
• SPECIAL OPTIONS — See datasheet page 94: 0 -  Single Length Probe (Non-Segmented)
• INSERTION LENGTH: 061 - 061" (1549,4mm)

Basic Ordering Information probe