The LK-MC600 series radar level gauge is suitable for measuring the level of liquid and solid media.

Even under high pressure or extreme temperature, they can accurately and reliably measure the level of liquid media. They can be used for conventional media, corrosive media, and applications with strict hygiene requirements. Even in the presence of dust and noise, the instrument can reliably measure light and heavy bulk solids without being affected by adhesives or condensation.

The radar level gauge adopts a transmission reflection reception working mode. The antenna of a radar level gauge emits electromagnetic waves, which are reflected at different intensities when they encounter the surface of the object being measured. The reflection intensity depends on the characteristics of the reflected object and is then received by the antenna. The time it takes for electromagnetic waves to be transmitted and received is proportional to the distance to the liquid surface. Continuous Frequency Modulation (FMCW) technology measures the level by converting the propagation time into frequency difference, and calculates the target distance by measuring the frequency instead of directly measuring the time difference. Transmitting a microwave continuous signal with linearly modulated frequency, the frequency rises (falls) linearly, and the received echo signal frequency also rises (falls) linearly. The frequency difference between the two will be proportional to the distance from the target.  

The frequency modulated signal is transmitted through the antenna to the surface of the measured material in the container. The received echo frequency signal is mixed with a portion of the transmitted frequency signal, and the resulting difference frequency signal is filtered and amplified. Then, Fast Fourier Transform (FFT) analysis is performed, which generates a spectrum. The echo is processed on this spectrum and confirmed.

Advantage

The LK-MC600 series instruments are not affected by noise, pressure, or temperature fluctuations during measurement, and are also not affected by density changes, bubbling, steam, or dust. The attachments on the probe or container wall do not affect the measurement. This makes the design and planning of the equipment simple and feasible. The guided operation instructions make debugging work not only simple, time-saving, but also reliable.

1.1 Application

LK-MC600 is a 2/4-wire, 140 GHz FMCW high-frequency radar level gauge used for continuous level measurement of solid materials in silos or silos.

The ideal solid level measurement product is suitable for various extreme working conditions such as heavy dust and high temperatures up to+400 ° C (+592 ° F).

Powdery, granular, fine or rough loose or stacked materials

1.2 Function

The advantages of using 140GH high-frequency radar over low-frequency radar are:

The beam angle is narrow, so the instrument can avoid interference from installation sleeves or silo obstacles

Short wavelength, excellent material surface reflection performance, so there is no need to align the material stacking angle

Adopting a lens antenna to avoid the influence of hanging and sticking materials; If necessary, compressed air can be used to blow and clean the interface regularly.

The signal is processed using process intelligence algorithms, which have been successfully validated in over 1000000 applications worldwide (ultrasonic and radar).

1.3 Characteristics

● Measurement range

Up to 150m (329 ft)

● Certification

Certification applicable to regular occasions and hazardous area applications

● Mechanical

Lens antenna and flange are easy to install and position

Stainless steel shell

Flat flange and aiming flange

● Service

Plug and play system, easy to install and test run

● Programming/Debugging

Parameter adjustment is carried out through the display screen and buttons.

Only 6 parameters need to be set.

After setting, the parameters can be copied to multiple instruments under the same operating conditions.

Parameter settings can be modified through the HART bus.

1 Installation

1.1 Basic Instructions for Instrument Use

Take the following measures to prevent moisture from entering your instrument panel:

▶  Please use the recommended cable (see "Connecting to power supply device")

▶  Tighten the cable threaded joint

▶  Rotate the shell in such a way that the cable threaded joint points downwards

▶  Guide the connecting cable downwards before the cable thread joint

This first applies to:

▶  When installing the instrument outdoors

▶  Installed indoors with moisture (such as during the cleaning process)

▶  Installed on cooled or heated containers

1.2 Installation Tips

When installing the LK-MC600 series frequency modulation radar, it should be noted that the distance from the container interior or container wall should be at least 300 mm (12 in) (except for installation in the bypass pipe). For non-metallic containers, the distance from the container wall should be at least 500 mm (19.7 in).

During the operation of the instrument, the measuring electrode must not come into contact with the device inside the container or the container wall. If necessary, the electrode end can be fixed.

For containers with a conical bottom, it is advantageous to install the sensor in the center of the container, as this allows for almost continuous measurement at the bottom. Note that it may not be possible to measure all the way to the tip of the measuring probe. The precise minimum distance value (lower dead zone length) can be found in the separate "Technical Parameters".

The measurement principle of guided microwave in plastic/glass containers requires a metal surface at the process joint. Therefore, please use instrument types with flanges (starting from DN 80) in plastic containers or place a metal plate (ø>200 mm/8 in) under the process joint when screwing in.

Note that the board should come into direct contact with the process joint.

When installing rod or rope type measuring probes without metal container walls and only plastic containers, the measured values will be strongly affected by electromagnetic fields (interference emission according to EN 6132: Class A). In this case, please use a coaxial measuring probe.

If possible, please avoid using container pipe fittings. Please install the sensor as flat as possible with the container lid. If this is not possible, please use a short pipe joint with a smaller diameter.

Those higher or larger diameter nozzles can generally be used. But they may increase the distance between the upper blocks, please check if this makes sense for your measurement.

In such cases, please always suppress interference signals after installation. For other information, please refer to "Debugging Steps".

2 Wiring Description

2.1 Wiring diagram for single chamber shell 24VDC power supply four wire system products

In the four wire system application, in addition to the 24V power supply terminal, the 4-20mA analog output is a separate two terminal. At the same time, the four wire system also provides 485 output terminals, which are convenient for connecting and debugging with PCs or on-site applications that require 485 interfaces.

2.2 Wiring diagram for single chamber shell 24VDC power supply two-wire system products

In the application of two-wire system, in addition to the traditional power supply terminal (4-20mA output), the instrument also has a serial communication terminal, which is convenient for connecting with mainstream IOT devices or transparent transmission devices for remote control and debugging.

3 Debugging Display Description

The LK-MC600 series performs level/liquid measurement tasks based on settings, which can be modified through the local display module (LDM). LDM consists of 4 buttons and a 128 × 64 dot matrix LCD.

3.1 Button Description

The system provides 5 operating interface modes:

【 Measurement Interface Run Mode 】: Display the system's operating status and current measurement data;

Echo Mode: Display the current measured echo status of the system;

[Memo Mode]: Display historical measurement data of system operation records;

[Setup Mode]: Set various data parameters for system operation;

[Input Mode]: Input the numerical value, number, or character of the parameter;

The functions of the four buttons are also different in different operating modes.

3.2 Measurement Interface Description

▶  Real time value: represents the real-time measurement results of the system; The result is converted from real-time distance information from the sensor reference point to the material level surface, and the conversion method is determined by the sensor mode and the high-low position adjustment point.

▶  Damping value: The smoothed output of real-time values after passing through a damping filter.

▶  Temperature: Indicates the temperature of the signal processing board.

▶  Version number: indicates the specific product model.

▶  Communication status: The heartbeat indicator of the system communication status, flashing once every 1 second is considered normal. If it does not flash or only flashes once for a long time, it indicates a communication fault.

▶  Unit: Refers to the system's distance measurement unit.

▶  Current value: represents the ideal 4-20mA current output value corresponding to the analog quantity to be tested. It is automatically converted by the system based on the high and low adjustment points and the 4-20mA current output function. For specific conversion relationships, please refer to sections 6.5.4. (6-8).

▶  Fault code: Please refer to Appendix A for specific meanings.

3.3 Echo Interface Description

In the measurement interface, press the [ESC] key to enter the echo interface

In the echo interface:

▶  The number represents the maximum echo intensity within the range (not necessarily the echo selected by the current algorithm). For a good metal reflector, the echo intensity should be around 70dB. If the echo intensity is less than 30dB, it indicates that the echo signal is weak and requires technical personnel to conduct corresponding troubleshooting.

▶  The real-time value and damping value of the echo interface are always measured in distance mode: that is, the distance value given is from the sensor reference point to the material level surface.