【2026 Instrumentation beside the tank】Radar level gauges are paired with display units installed beside the tank – in which situations is it mandatory to install them, in which situations is it recommended to do so, and in which situations can they be omitted?

Function of the display unit beside the tank: The mainstream radar level gauges, servo level gauges, and magnetostrictive level gauges used in factories today are primarily designed to accurately collect level data, transmitting 4-20mA signals to the central control system. Most of the equipment units do not have local visual screens, so field inspectors who arrive at the tank area are unable to directly read real-time level and temperature data on site. Once there is a failure in the central control communication, a power outage, or signal fluctuations, the site will fall into a \"blind tank\" state, making it impossible to quickly assess the condition of the storage tank, which poses significant safety risks. The display unit next to the tank is a device specifically designed to address the critical need of having data available for remote transmission while still allowing visibility at the site.

Operating conditions for tanks that are mandatory to be installed: 1. Pressure tanks and liquefied hydrocarbon spheres must, in accordance with the industry standard SH/T 3007, be equipped with both remote monitoring and local indication systems. For such high-risk storage tanks, it is strictly prohibited to rely solely on remote data from the control room. Moreover, conventional glass plate level gauges have a high failure rate and poor safety features; therefore, digital display units installed near the tank represent the optimal solution for local monitoring, and their presence is a mandatory requirement during inspections.

2. For storage tanks of flammable and combustible liquids, in accordance with the safety standard AQ3053, tanks that store flammable and explosive materials must be equipped with functions for real-time local display as well as high and low liquid level alarms, with the data being synchronized and transmitted to the control room. Such storage tanks are considered high-risk hazards that require close supervision; relying solely on central control systems is insufficient to meet the needs of on-site inspections and emergency response, so installing display units next to the tanks is a basic requirement for ensuring safety and compliance.

3. Large-scale metering tanks: Raw material tanks, finished product tanks, and trading metering tanks with a volume of ≥100 m³, as well as large tanks with a volume of over 100,000 m³, are considered core equipment for production metering. The regulations require continuous level monitoring along with on-site readable displays, to ensure that the measurement data can be verified and traced, thereby preventing errors in trade settlements and production batching. For large storage tanks, it is also recommended to use a dual-instrument redundancy setup.

Recommended operating conditions for installation beside the tank: 1. Difficult access for climbing, and a highly hazardous environment in the tank area. Most storage tanks are over 6 meters tall, making it extremely risky to climb up them to take readings; moreover, the tank areas are often environments characterized by explosion hazards, high temperatures, toxicity, and flammability. By installing a display unit next to the tank, it is possible to read the data directly on the ground, thereby completely eliminating the risks associated with working at heights and ensuring the safety of inspection personnel.

2. Core storage tanks that require frequent operations and high-frequency inspections: tanks used for loading and unloading, blending, and intermediate buffering – such as those that are used in frequent operational activities – require real-time verification of liquid level data whenever pumps are started or stopped, materials are switched, or ratios need to be adjusted. With a display panel next to the tank, inspectors and operators can quickly verify the data on-site without having to go back and forth to the control room, which greatly improves operational efficiency and helps avoid mistakes in operation.

3. Frequent adjustments, calibration, and maintenance of instruments. During routine calibration, circuit testing, and fault diagnosis of instruments, the lack of on-site display requires real-time communication and cooperation between personnel at the site and those in the control room, which is time-consuming and labor-intensive. The display unit adjacent to the tank provides real-time synchronization of the actual liquid level and current signals on site; debugging and calibration can be carried out by a single person, thereby significantly reducing the complexity of operation and maintenance.

4. As a backup solution for remote transmission systems, unexpected situations such as power outages in the control system, communication disruptions, and signal drift can occur during production. In such cases, the remote transmission of data is disrupted, and it becomes very easy for the storage tanks to lose control. The display unit located next to the tank can provide independent on-site display, serving as the final line of defense for condition monitoring and ensuring that the situation can still be controlled and monitored in case of unexpected failures.

Conditions where no additional display unit beside the tank is required: Not all radar level gauges need to be equipped with a display unit adjacent to the tank. In the following low-risk scenarios, such an additional unit is unnecessary, thereby saving on project costs: small storage tanks at atmospheric pressure (volume < 100 m³), which are not high-risk, not used for measurement purposes, and are not critical to production processes； The site is equipped with qualified and effective local level indication devices such as magnetic flip plates and glass plates ； Unmanned, low-frequency inspection, auxiliary storage tanks that require no on-site operation ； Used only for simple monitoring; ordinary storage tanks that require no emergency response or measurement verification.

The display unit placed next to the tank may appear to be a small auxiliary instrument, but it is in fact a key device for ensuring the safety and compliance of storage tanks, enabling efficient operation and maintenance, and providing emergency support.