Magnetostrictive level gauge (using the Wademan effect principle)

Ⅰ. Overview
 
1, working principle:
      The magnetostrictive level gauge uses the principle of Wademan effect (magnetostrictive working principle) to accurately measure the time value between pulse waves through modern advanced electronic technology to achieve accurate liquid level measurement (see below) Figure). The liquid level meter produced by this principle is the most accurate, simple, stable, reliable and mature product in the field of measuring liquid level. Especially in the general environment such as small range, normal temperature and normal pressure, it is more unique and is incomparable to other measurement methods.

2. Structure:
      The magnetostrictive level gauge consists of four parts: an electronic transmitter, an interface float, a probe, and a display instrument. The first three parts must be purchased. The display instrument is determined according to the purpose of use, and can be purchased or replaced by a common computer. The installation software (or user-customized software) provided by our company can realize centralized display (or separate display) and control. The length of the "probe" rod is customized according to the user's range. Use this instrument in an environment where explosion-proof requirements are required. The power supply circuit must be equipped with a safety barrier.
You can also purchase the safety power supply of the intrinsically safe explosion-proof grade produced by our company.
  
Ⅱ, the characteristics
  
1. High stability, high reliability and high precision;
2, compact structure, simple installation, convenient, maintenance-free;
3, anti-electromagnetic interference, anti-liquid fluctuation interference;
4. Cost-effective: One sensor can measure the liquid level of two or more media and the average temperature of multiple points at the same time.
5, anti-corrosion, high temperature design, long life and so on.
  
Ⅲ, the main performance
  
Range: 0~12500mm;
Accuracy: ±0.5mm
Resolution: 0.1mm
Ambient temperature: -25 ° C ~ 70 ° C
Process interface: 3/4′′ NPT
Mounting interface: thread M26*2 (M27*2), M28*1.5
Power supply: DC24V
Output signal: 4~20mA, two-wire system, three-wire system, four-wire system
Temperature measurement: -35 ° C ~ 125 ° C
Temperature error: ±0.5 °C
Explosion-proof grade: ExiaIIBT4
Communication: RS-485, RS-232, Modbus,
Can be equipped with CAN bus or according to user requirements.
  
Ⅳ, the installation
  
Typical installation
  
A, the head fixed fittings installation: connecting thread M27*1.5 (M28*2)
B. With movable connection fittings installation: connecting thread M28*1.5
Installation conditions
  
(1) Underground horizontal tanks for applications such as gas stations
  
● The sensor should be installed away from the unloading pipe, submersible pump or self-priming pump pipe installed in the tank to prevent fluid.
Direct impact
● The sensor installation position should be selected on the central axis of the longitudinal direction of the tank to reduce the dead zone.
●The sensor installation position should be selected close to the gauge hole to ensure the same measurement standard.
● Sensor mounting hole diameter: Should be larger than the diameter of the float, the requirement for the gas station is DN100mm.
 
(2) Above-ground vertical tanks for applications such as oil depots and refining and chemical enterprises
  
● The sensor installation position should be away from the inlet and outlet oil (material) port. It is recommended that the angle between the sensor installation position and the inlet and outlet oil (material) port be between 45 degrees and 135 degrees to prevent the fluid from directly impacting the float;
  
● The installation position of the sensor should be within the range of 900mm~1200mm from the tank wall, that is, the temperature measurement caused by avoiding too close to the tank wall is inaccurate, and it is necessary to avoid the measurement of the liquid level due to the deformation of the tank bottom near the tank. Necessary influence
  
●Because the current actual situation is: use the manual ruler to complete the initial calibration of the liquid level gauge measurement, so the sensor installation position should be kept on the same circumference as the gauge hole, and as close as possible to the gauge hole to ensure the two The measurement benchmarks are basically the same.
  
● For new tanks, it is required to install the anti-shock baffle at the bottom of the tank level. The impact baffle diameter is
300 mm and height at 200 mm.
(3) For industrial control tanks with mixers or medium fluctuations, the protective pipe should be added or the side pipe installation should be adopted.
(4) For inner floating tray
  
● The center of the inner opening of the floating plate should be on the same axis as the center of the mounting hole of the liquid level gauge;
 
●The opening diameter of the inner floating disc is ≥300mm;
  
● Install a splash-proof extension tube (100~150mm high) at the opening of the inner floating plate to prevent oil from spilling onto the upper surface of the floating plate. Install a sealant plate on the top of the extension tube to prevent oil and gas from evaporating. When installing the sealant sheet, ensure that the sealant sheet does not touch the float and affect the accuracy of the measurement;
  
●The top of the inner splash-proof tube is sealed with double-layer sealing rubber plate. The single-layer sealing rubber plate is opened according to the word “ten”. The length of the cross opening should ensure the passage of the float and the weight. The thickness of the single-layer rubber plate is ≥4mm. The openings of the two layers of rubber sheets are placed in a "m" shape and placed in an overlapping manner.
  
Ⅴ, common fault status and release:
  
1. When the indicator of the digital-to-analog conversion module flashes once every ten seconds, the status is the fault diagnosis status.
 
How to cancel:
Please check the data cable connection status of the sensor to determine whether the sensor power supply is normal (normal power supply: 22.5~25.5VDC)
. If not, replace the standard power supply or adjust to the normal state.
 
2. When the indicator of the digital-to-analog conversion module blinks for one long and two short, the state is no float state.
  
Release method: Please check the float status or adjust the adjustable potentiometer in the sensor board (104 adjustable potentiometer):
  
1. Adjust clockwise to increase the sampling voltage:
Generally, when data can be collected, but the data is unstable and the jitter is relatively large;
  
2. Counterclockwise adjustment to reduce the sampling voltage:
Generally, it is to solve the problem that the float is located at the lower end of the sensor without signal output.
  
3. Sensor fault monitoring method
 
1 Connect the data end of the digital-to-analog converter (ie data A, data B) with RS485 communicator, baud rate: 4800, data bit: 8
, Validation bit: None, stop bit: 1, Send mode: HEX, Receive mode: ASCII 2 Power on the sensor and digital-to-analog converter (24VDC), the serial debugging software should return:
 
E.g:
  
RD:??(16:43:00:171)
:
RD: 440.2: E505: E507? (16:43:00:421)
Among them: 440.2 is the height value of the liquid level float, the unit is mm (when the potentiometer is adjusted, the value is stable and does not jump. It is generally recommended that the potentiometer rotates slightly 1/4 turn counterclockwise after the value is stabilized). E505 is the interface float fault code, meaning no float (the height value is displayed when there is an interface float, the same as when adjusting the potentiometer) E507 is the read temperature error (when there is temperature display temperature value).
 
※Remarks: When using, it is best to use independent 24V power supply, while keeping away from electromagnetic interference and ensuring good grounding.
  
Ⅵ, product features and application areas
  
1) Product features
  
*Internal non-contact measurement
*High performance and price ratio
* A variety of output options are available
*Anti-surge, anti-radio frequency interference
* No need for regular calibration and maintenance
* Easy to install
*High precision, high stability, high reliability
*long lasting 
*Structural structure and strong environmental adaptability
*Intrinsically safe explosion-proof type
* Isolated explosion-proof type (optional)
2) Application area (displacement)
  
*Servo hydraulic cylinder piston position feedback
* Grinding mechanical position feedback or preset
* Wood processing positioning control
*Detection and control of turbine guide vane opening
* Paper and plastic film molding
*Squeezing mold machinery
*Blow molding
*Engineering machinery
*Metal forming / shear stamping
*Other mechanical positioning and displacement detection
* dam gate
*Servo cylinder piston position feedback or preset
* Casting and forging machine displacement control
* Injection molding machine template positioning and monitoring
*Detection of turbine opening resistance valve opening
* Glass pressing
* Plastic mechanical transformation
*Pneumatic cylinder
*Steel rolling
*food processing 
* Ship steering servo system
 
3) Application area (liquid level)
  
     It can be widely used in liquid level gauges of various liquid tanks in petroleum, chemical, water conservancy, pharmaceutical, food, beverage and other industries.
Quantity and control, aerospace refueling system, automobile refueling system, diesel refueling system and various hydraulic tanks, hydrological supervision
Level measurement and control of measurement, water treatment, acid, alkaline liquid, etc.