Magnetrol Eclipse 706 GWR - Guided Radar Level Transmitter 706-511A-010 +

7AS-11K0-A2N-20-030

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 is likely an old model of a guided wave radar (GWR) level transmitter, which operates by emitting microwave pulses from a probe, calculating the time for these pulses to reflect off the liquid's surface and return, and translating that time into a precise level measurement. The "7AS" designation suggests a product line or a specific feature code, but the core principle remains the same as other GWR systems: the device sends a signal, the signal reflects off the liquid, and the time it takes to return indicates the level.

How it works:

1. Signal Emission: A probe extending into the tank (the guided wave radar probe) generates and directs microwave pulses downwards into the vessel.
2. Signal Reflection: When these pulses encounter the discontinuity between the gas/vapor in the headspace and the higher dielectric constant of the liquid or solid, they are reflected back to the transmitter.
3. Time Calculation: An integrated timing circuit measures the time it takes for the pulses to travel from the antenna to the liquid surface and return.
4. Level Measurement: The transmitter uses this time-of-flight data to calculate the precise liquid level within the tank

Key aspects of GWR technology:

• Non-contact (mostly): The probe itself is in contact, but the signal transmission and reception are a form of radar, making it distinct from purely magnetic or ultrasonic methods.
• Accuracy: GWR technology is known for its high accuracy and reliability in a wide range of applications.
• Versatility: It can measure various liquid and solid levels, even in harsh process environments.
• Advanced features: Modern GWR transmitters often include advanced features like echo curve analysis to provide more detailed data for troubleshooting

 Full Datasheet Devices

Transmitter Feature  

• Manufacturer :  Magnetrol 
• Product No. : 706-511A-010
• 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 certification
• ACCESSORIES/MOUNTING: A -Digital Display and Keypad - Integral
• CLASSIFICATION: 0 - General Purpose, Weatherproof (IP 67)
• 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-11K0-A2N-20-030
• 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: K - ASME B31.1 — NOT available with 4th digits T or U
• FLANGE OPTIONS: 0 -  none
• MATERIAL OF CONSTRUCTION - FLANGE/NUT/ROD/INSULATION: A -  316 SS/316L 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: 0 -  Viton® GFLT — Only Available with 3rd digit T
• INSERTION LENGTH: 030 - 030" (762mm)

Probe Drawing 

Basic Ordering Information probe