1. Overview
Sincerely thank you for choosing our companyUltrasonic level gaugeYe Li is a professionalUltrasonic level gauge manufacturer，Moreover, the price of ultrasonic level gauges is favorable, and large quantities are preferred,Please request a quote for the ultrasonic level gauge from customer service！This instrument contains multiple patented technologies, which are characterized by safety, cleanliness, high accuracy, long service life, stability and reliability, and easy installation and maintenance. It is suitable for acids, alkalis, salts, etcantisepsisDomain.
This instrument can be connected to display meters or various DCS systems through 4-20mA or RS485 (Modbus protocol or other customized protocol), providing real-time liquid level data for industrial automation operation.

Ye Li'sUltrasonic level gaugeHas the following characteristics:
The circuit design selects high-quality power modules and imported high stability components from the power supply section onwards. The YEH-HK series ultrasonic level gauge can almost replace similar imported instruments from abroad.
The patented sound wave intelligent technology software can perform intelligent echo analysis without any debugging or other special steps. This technology has the functions of dynamic thinking and dynamic analysis.
Our company's patented sound wave intelligent technology greatly improves the accuracy of instruments, achieving liquid level accuracy of0.25%～0.5%.
This instrument is a non-contact product that does not come into direct contact with liquids, resulting in a low failure rate. The instrument provides multiple installation methods, and users can choose freely through this manual.
All input and output lines of the ultrasonic level gauge have lightning protection and short-circuit protection functions.

2.1 Technical indicators of two-line ultrasonic level gauge
Measurement range: 5m, 10m, 15m, 25m (selected according to the actual measurement range)
Blind zone: 0.25m to 0.8m
Distance measurement accuracy: 0.25% to 0.5% (standard conditions)
Distance measurement resolution: 1mm
Pressure: below 4 atmospheres
Instrument display: Equipped with LCD to display liquid level or spatial distance
Analog output: 4-20mA
Digital output: None
Power supply voltage: DC24V/1W, built-in lightning protection device
Environmental temperature: -20 ℃~+60 ℃. High temperature can be customized (temperature resistance up to 90 ℃ can be customized)
Protection level: IP65 or IP68

2.2 Technical specifications of four wire ultrasonic level gauge
Measurement range: 5m, 10m, 15m, 25m (selected according to the actual measurement range)
Blind zone: 0.25m to 0.8m
Distance measurement accuracy: 0.25% to 0.5% (standard conditions)
Distance measurement resolution: 1mm
Pressure: below 4 atmospheres
Instrument display: Equipped with LCD to display liquid level or spatial distance
Analog output: 4-20mA
Digital output: RS485, Modbus protocol or custom protocol
Relay output: Two independent outputs
Power supply voltage: DC24V/AC220V, built-in lightning protection device
Environmental temperature: -20 ℃~+60 ℃. High temperature can be customized (temperature resistance up to 90 ℃ can be customized)
Protection level: IP65 or IP68

Example of the function of the four wire ultrasonic level gauge relay:
(1) When the liquid level is below 2 meters, close the relay and start the pump to inject water. When it is above 7 meters, disconnect the relay and stop the pump.
It can be implemented using a lower limit alarm relay, with a return difference dL set to 7-2=5 meters and L set to 2 meters. When the liquid level is less than 2 meters, the relay will close and the pump will start to inject water. When the liquid level exceeds 7 meters, the relay will disconnect and the pump will stop.
(2) At a liquid level of 5 meters, if it is higher than 4 meters, close the relay to open the pump for drainage. If it is lower than 1 meter, disconnect the relay to stop the pump.
It can be achieved using an upper limit relay. Set hysteresis dH=4-1=3 meters, H=4 meters. This allows the relay to close and start the pump for drainage when the liquid level is greater than 4 meters, and stop the pump when it is less than 1 meter.
The above two examples are both examples of using hysteresis control to control two liquid level points when only one pump is used. For situations where multiple pumps are used, simple control values can be set.

3. Installation method:
Under open working conditions, bracket installation is generally used, and this product comes with a locking mechanismnutOr independently customize flange installation. Cut a circular hole slightly larger than the probe diameter at the installation of instruments in the pool or tank（60mm）Insert the ultrasonic level gauge probe and thennutperhapsflangeTighten from bottom to top. The installation must ensure that the probe surface of the ultrasonic level gauge is perpendicular to the measured liquid level. Common YEH-HK seriesUltrasonic level gaugeThere are three installation methods to choose from.

Extension pipe installation
If the measured liquid level is within the blind zone range, the probe must be installed on the extension tube.
The diameter and length of the extension tube are limited. See the following figure for details.
Avoid condensation and adhesion inside the extension tube.
Ø Smooth the inner surface of the extension tube as much as possible（No welding points and various seams）
The extension pipe mouth must be smooth. A 45 degree angle is ideal.

【 Installation reference diagram 】

Installation of waveguide tube
If there is strong echo interference on site (such as in narrow shafts, unavoidable steps, etc.), it is recommended to use ultrasonic waveguide pipes with a diameter greater than 100mm (such as PE or PVC sewage pipes). Smooth inner surface of waveguide as much as possible（No welding points and various seams）. There are ventilation holes at the top. A 45 degree angle at the mouth of the pipe is ideal. Ensure that the waveguide is not dirty, and if necessary, clean the waveguide regularly.

On site installation case


4. Instrument wiring
(1）Two wire instrument wiring:Please note: Do not use the same DC24V power supply as the frequency converter, and ensure that the negative terminal of the power supply is well grounded. If there is an isolator, it would be better. As shown in Figure 1:
(2)Four wire instrument wiring:Open the back cover to seeUltrasonic level gaugeThe wiring board. As shown in Figure 2:


5. On site physical reference: