A level transmitter is a device that generates an electrical signal proportionate to the volume of a contained solid or liquid. Output can be generated either once for each measurement or when a predetermined value is reached (continuous level). Level transmitters can gauge the height of liquids like water, viscous fluids, and fuel and dry media like bulk solids and powders.
There are several uses for level transmitters, which measure the liquid or gas level in storage tanks and other containers. Many industries use level transmitters, including the food and beverage, chemical, water treatment, power, and material handling sectors.
When choosing a level transmitter, it is important to consider the device’s output compatibility and measuring range.
Output
Each level transmitter has an individual output signal tailored to work with a certain sensor and indicator/meter. The following are examples of typical outputs:
One of the most typical sensor outputs is a current loop. Due to their high power and relatively long transmission distance, 4-20 mA outputs are widely used in fields like process control. Since current signals are unaffected by voltage drops in the system wiring, they can also be used to power measuring instruments.
Some research suggests that digital signals employing the Highway Addressable Remote Transducer (HART) protocol could improve analog current loops.
Current loops have been superseded by Fieldbus protocols, which are digital communications standards. FOUNDATION Fieldbus, Modbus, and Profibus are just a few examples. Some examples of frequency signals are pulse trains, sine waves, and AM/FM broadcasts.
Liquid Measurements
Here we will go over the four primary technologies used for measuring liquid levels.
Capacitance
Evaluates the level-dependency of the conductivity of the current. The value depends on the dielectric constant of the fluid.
Advantages
- Super simple to set up
- Perfect for slurries and liquids with solid particles.
Disadvantages
- Non-metallic storage tanks pose significant challenges.
- The measuring range is restricted by the dielectric constant.
- Longer probes are required.
Pressure
Provides a reading of the water pressure in relation to the height.
Advantages
- It works wonderfully with frothy or turbulent media.
Disadvantages
- It can only be used with non-pressurized tanks and fluids with a low viscosity.
Radar
Transmits signals in order to receive their reflections, a process known as temporal domain reflectometry (TDR).
Advantages
- Rapidly deployable
- Suitable for solids and liquids alike.
- Contamination-resistant.
Disadvantages
- The length of the probe needs to equal the whole sensing range.
- Expensive.
Ultrasonic
A method that uses the delay in sound waves between their emission and reflection to calculate volume.
Advantages
- Non-contact measurement
- Perfect for use with thick substances
- Typically, you can set the entire range of your instrument’s measurements to whatever you like.
Disadvantages
- Inadequate for use with pressure tanks or liquids that generate a lot of steam or froth.
Based on the advanced technology, Micro Sensor has designed and manufactured various types of level transmitters and level transducers with quality and reliability.
Submersible Level Transmitters
Submersible level sensors continuously provide precise water depth readings in tanks of virtually any capacity. Submersible level sensors function by gauging the hydrostatic pressure of the tank’s contents. Knowing a fluid’s density and height allows one to calculate the hydrostatic pressure exerted on it. If we assume that the liquid’s density does not vary, then the reason for the shift in hydrostatic pressure is the volume of the liquid above the tank’s base.
Non-pressurized or vented tanks are used in applications with variable air pressure. The atmospheric pressure over the fluid line affects the hydrostatic pressure of the tank and the liquid level. For this reason, submersible-level transmitters are equipped with their venting to compensate for the differential and maintain accurate readings.
Digital Level Transmitters
Level transducers, sensors, and transmitters with intelligence typically provide digital RS485, Modbus, or HART output signals. Digital level transmitters can be used to gauge the contents of any container, be it a water tank, oil container, storage container, etc.
This high-precision, digitally controlled level sensors are protected against moisture and corrosion by an IP68 rating. Consequently, they can be used as level sensors for industrial, marine, underground liquids, etc.
Thin Diameter Level Transmitters
Thin-type level transmitters are level sensors with narrow profiles. For applications like level monitoring that need compact dimensions and precise readings, sensors with widths of 17, 19, and 22 millimeters are ideal.
Despite its small size, it measures levels in deep wells, boreholes, and underground water with precision and stability.
Special Application-Level Transmitters
Those needing specialized-level transmitters can turn to us for a reliable product. The MPM426w Series level transmitter and the MPM436W level sensor are ideal for keeping an eye on levels down to 0.5 meters. Similarly, to temperature transmitters, the MPM4810 and MPM4811 are dual-level transducers.
Neither the radar level transmitter nor the ultrasonic level transmitter is required if you’re searching for a contactless level reader. These level sensors and transducers have many uses, including detecting portable sewage and water in the petrochemical industry, power plants, municipal water systems, sewage treatment plants, hydrology, and other fields.