KAIDI high-quality guided wave radar level transmitter principle of operation suppliers for work

I. The Measurement Principle：

Microwave antenna to receive the reflected pulse and transmitted to the electronic circuit, a microprocessor to signal processing, to identify the micro pulse generated on the material surface echo. Echo recognition is completed by the pulse system, the accuracy can reach millimeter level. From the material surface distance between D and T pulse is proportional to the time travel:

D=C×T/2

Where C is the speed of light

Because of the air tank is a known distance E, L:

L=E-D

By setting the empty tank height E (= zero), the full height of F (= full scale) and some application parameters, application parameters automatically makes the instrument to measure the environment. 4 - 20mA with a corresponding output.

l  Application:

6GHz radar level gauge is suitable for liquid, paste, granule and block material level and non-contact measurement, suitable for changes in temperature, pressure big; there is an inert gas and volatile.

The measurement method of microwave pulse, can work normally in the industrial frequency band range. The beam energy is low, can be installed on all kinds of metal, non-metallic container or pipe, no harm to human body and environment.

II. Product  Introduction

• 801

• 802
  

• 803

• 804

• 805

• 806

 III. Installation Guide

• Installation instructions:

  

     Ø  The recommended position (2), the outer wall of tank wall to install pipe shall meet the following from the tank wall best distance to tank diameter of 1/4 or 1/6, the minimum distance from the installation of tank wall as the measurement range of 1/10.

Ø  For example: liquid level of storage tank 10m, and the tank wall install the minimum distance of 1m.

Ø  Cannot be installed above the feeding port (4).

Ø  Cannot be installed in the central position (3), if installed in the central, yield multiple false echo, clutter echo will lead to real signal loss.

Ø  If you can't keep the instrument and the tank wall of the tank wall distance, the medium will adhesion caused by false echo, when debugging instrument should be false echo storage.

l  The top conical tank level, can be installed at the top of the tank is intermediate, can guarantee the measurement to the conical bottom.

A feed antenna to the vertical alignment surface. If the surface is rough, stack angle must be used to adjust the angle of Universal joint flange of the antenna to the alignment surface.

(Due to the solid surface tilt will cause the echo attenuation, even Loss of signal.)

• Tank installation instructions:

  
  

Ø  In the signal beam, should avoid the following installation: 

Such as: (1) the limit switch, temperature sensor. 

Ø  Symmetric devices such as (2): vacuum ring, a heating coil, Baffle plate etc.

Ø  If the tank (1) (2) interference object, should be guided wave tube measurement.

Best installation options:

Ø  Antenna size: larger antenna, beam angle smaller, interfering echoes will be weaker.

Ø  Antenna adjustment: the antenna to adjust to the best measurement position.

Ø  Guided wave radar take over: The installation of the wave guide is used to avoid disturbing the echo.

• Tank installation (801, 802)

A standard installation

Ø  The radar antenna cannot tilt to the tank wall.

Ø  In order to minimize temperature effect, at the junction of butt joint flange must use the spring washer.

Ø  The rod antenna launching point must reach out to install pipe.

Ø  The vertical placement of the rod antenna beam direction, don't let the tank wall.

Install short long antenna extension tube

Ø  When the horn length is less than the installation of tube length, tube using antenna

Ø  If the diameter of the horn tube diameter greater than the installation, you will need to increase meter elevation, extension tube. The antenna and the extension tube needs to be installed from inside the container. Select the extension tube makes the instrument at least elevation 100mm.

• Measurement of Wave Guide Tube：

  If there is an obstacle, such as a ladder, limit switches, heating equipment, such as a stent within the range of the microwave beam emitted radiation will lead to measurement errors. If affected, the need to add another wave guide measured.

         Then measure the wave guide tube (or Bypass pipe) installed inside the container to avoid obstacles, foam, liquid surface fluctuations and large impact on the measurement.

                Note: 

               Isobaric pore diameter 5 ~ 10mm.

                      Wave guide diameter of at least 50mm, and the inner walls must be smooth.

                    Measuring only good mobility media, viscous media cannot be measured with a wave guide.

• The bypass pipe installation

Ø  If the sensor is installed in the bypass pipe, need to install the communication part is higher than that of the by-pass pipe and the upper part of the container ≥ 500mm; by pass pipe at the bottom to be lower than the connecting part of the by-pass pipe and the bottom of the container  ≥300mm.

Radar installation site display unit and connected component parallel.

Ø  If the dielectric constant of the medium small (< 4), part of radar signal can penetrate the dielectric constant dielectric. Echo signal when the tank bottom reflection signals when compared to the dielectric reflection of strong, at this time, measurement error. In this case, can be at the bottom of the tank to install refraction board will signal refraction.

• Typical installation errors：

Ø  Conical tank cannot be installed above the feed port. 

Note: outdoor installation should adopt sunshade. 

Ø  The instrument cannot be installed in the arched or domed roof intermediate. In addition to produce indirect echo is also affected by the echoes. Multiple echo can be larger than the real value of signal echo, because through the top can concentrate multiple echo. So cannot be installed in a central location. 

Ø  There are obstacles affecting measurement needed reflection plate.

• Below is a schematic diagram of the echo signal:

IV. Dimensions of Instruments

• The rod antenna radar size (unit: mm)

• The rod antenna radar size (unit: mm)

• Horn antenna size (unit: mm)

• Horn size (unit: mm)

• Flange Selection (unit: mm)

V. Measurement Conditions

Matters needing attention:

l  The general measurement range is calculated starting from the bottom of the tank, under special circumstances, if the tank bottom is a concave or conical, when the level below this point cannot measure.  

l  Low dielectric constant in a low level, the bottom of the tank can be seen, this time in order to ensure the measuring precision, suggestions will be zero shift.   

l  Measurement of antenna theory to the position Of the tip is possible, but taking into account the effect of corrosion and adhesion, the measuring range of the tip distance of  ≥ 100mm.

l  For overflow protection, can define a safe distance and dead area.

l  The minimum measurement range has relation with antenna.

l  Different concentration, foam can absorb microwave, also can be reflected, but under certain conditions can be measured. 

l  When no echo signal, the output current is 22mA.

VI. The Electrical Connection

• The power supply voltage:

(4~20)mA/HART (Two wire system)       The power supply and the output current signal sharing a two core shield cable. The supply voltage range see technical data. For intrinsically safe type must be a safety barrier between the power supply and the instrument.

(4~20)mA/HART(Four wire system)        Separate power supply and the current signal, respectively using a two-core shielded cable. The supply voltage range see technical data.

RS485 / Modbus                                      Power supply and Modbus signal line are separated, respectively using a two-core shielded cable, the power supply voltage range see technical data.

• Connection mode:

Ø  24V two wire wiring diagram as follows:

Ø  220V four wire connection is as below:

Ø  24V RS485/Modbus wiring diagram as follows:

• Explosion Proof Connection

  The intrinsic safety version sensors (Exia IIc T6) use Alu-die casting housing and filling Silicone rubber sealants internal structure aimed to prevent sparks resulted from circuit failure from leaking out. It is applicable for the continuous level measurement of flammable medium under Exia IIc T6.

  A safety barrier FBS-2 must be used together with the intrinsic safety instrument. It is an associated device to this product for the power supply of this product. The main specification is intrinsic safety: Exia IIC, voltage of power supply: 24V DC±5%, short-circuit current: 135mA, operating current: 4...20mA.

  All cables must be shielded. The max length is 500m for the cable from the barrier to the sensor. Stray capacitor≤0.1μF/Km, stray inductance 1mH/Km. Instrument must be connected to the ground potential. Any unapproved associated device is not allowed to be used.

• Safety instructions:

Ø  Please observe the local electrical code requirements!

Ø  Please comply with local requirements for personnel health and safety regulations.

All electrical components of instrument operation must be completed by the formal training of professionals.

Ø  Please check the instrument nameplate to provide product specifications meet your requirements. Please make sure that the power supply voltage and instrument nameplate on the requirements.

• Protection grade:

This instrument meets the protection class IP66/67 requirements, please ensure the waterproof cable sealing head. The following diagram:

How to install to meet the requirements of IP67:

Please make sure that the sealing head is not damaged.

Please make sure that the cable is not damaged.

Please make sure that the cable for use with electrical connection specification.

Cable into the electrical interface before its curved downward, ensure that the water will not flow into the shell, see the①

Tighten the cable seal head, see the②

Please electrical interface will not use blind plug tight, see the③

VII. Programming and Debugging

• There are three kinds of debugging method:

  1)     Display / Keyboard  

  2)     Host debugging  

  3)     HART handheld programmer 

• Display / Keyboard:

Please debug the instrumentation by four buttons on the display screen. There are three debug menu languages optional. After debugging is generally used only for display, through the glass window can read measured value very clearly.

Display / Keyboard

①
Liquid crystal display(LCD)

②
The key

• PC debugging:

Connected to PC by HART

①      RS232 interface or USB interface                     

②      Radar level meter

③      HART adapter

       4     250 Ω resistor

• HART handheld programmer:
  

①      HART handheld programmer

②      Radar level meter

③      250 Ω resistor

VIII. Technical   Parameters

General Data

Materials

Antenna                                                 PTFE, PP

Shell                                                      Aluminum, plastic, Anti-static PP, Stainless steel 316

The seal housing and the housing        Silicone Rubber

Shell window                                         Polycarbonate

Ground terminal                                    Stainless steel

Process connection 

801                                                      G1½″A Thread & 1½″NPT Thread / Flange (optional)

802                                                      With PTFE plate flange

803                                                      Stainless Steel Flanges

804                                                      Stainless Steel Flanges

805                                                  Stainless Steel Flanges

806                                                  Stainless Steel Flanges

Supply voltage

Two-wire       

Standard                                         (16～26)V DC

Intrinsically Safe                              (21.6～26.4)V DC

Power Consumption                        max.   22.5mA

Allowable ripple

- <100Hz                                         Uss < lV

- (100～100K)Hz                             Uss < l0mV  

Flameproof

(22.8 ~ 26.4) V DC       2-wire system

(198 ~242)V AC   4-wire system / 110V AC    4-wire system

Power Consumption                        max.  1VA，1W

 Cable parameters     

                     Cable entry / plug                           1 M20xl.5 cable entry (cable diameter 5 ~ 9mm)

                                                                            1 blind blocking M20xl.5

                    Spring terminals                               For wire cross-section 2.5mm²

 Output parameters

The output signal                             (4～20)mA / HART

Resolution                                       1.6μA

Fault signal                                      Current output unchanged；20.5mA；22mA；3.9mA

Two-wire load resistor                     See below

Four-wire resistive load                   The maximum 500Ω

                    Integration time                                (0 ~36) s, adjustable

Two-wire load resistor map

 Characteristic parameters

Blind                                         Antenna end

The maximum measuring distance  

801                                           20m（Liquid）

802                                           20m（Liquid）

803                                           35m

804                                           35m

805                                           20m

806                                           15m

Measurement interval               About 1s (depending on the parameter settings)

Adjustment time                        About 1s (depending on the parameter settings)

Resolution                                 1mm

           Accuracy                                   10mm &＜0.1%  (See schematic below precision)

Accuracy schematic

          801,802 Accuracy

          803 Accuracy

Working storage and transport temperature             (-40～80) ℃

Process temperature (the temperature of the antenna portion) 

801                    (-40～130)℃

802                    (-40～130)℃ Standard type / (-40～180)℃  High temperature type  

803                    (-40～130)℃ Standard type / (-40～250)℃  High temperature type

804                    (-40～130)℃ Standard type / (-40～250)℃  High temperature type

805                    (-40～130)℃ Standard type / (-40～250)℃  High temperature type

806                     (-40～400)℃

Relative humidity                               ＜95% 

Tank pressure                                   Max.  4MPa

           Seismic                                             Mechanical shockl0m/s² , (10～150)Hz