Simultaneous display of on-site liquid level and fire control room at the 6979 Commercial Center

System Requirements Analysis
According to the trial version 4.2.2, Article 4 and 4.2.3, Article 9 of the "Regulations on the Inspection and Evaluation of the Installation Quality of Fire Protection Facilities in Buildings" (DB37/242-2008), the water level of the fire water pool and fire water tank should be displayed in the fire control room. The importance of ensuring that the fire water pool and high-level fire water tank are full and can be remotely monitored in the fire control center is crucial. If the fire control room does not have a liquid level indicator for the fire water pool and high-level fire water tank, it may fail the acceptance inspection of the building fire protection facility installation quality, according to the fire regulations. Therefore, it is necessary to monitor the real-time water level of the fire water pool and tank in the fire control room, which requires the use of the WH311 fire water tank level indicator.

System Overview
The WH311 level sensor probe is directly placed at the bottom of the user's fire water pool and tank, and the WH6 fire-dedicated level indicator is installed in the fire control room. They are connected by a 2*1.5 square shielded cable to display the real-time fire water level and has a built-in high and low level alarm system to ensure the fire water level remains high.

Application Challenges:
1. Electromagnetic interference exists in the monitoring scenario;
2. The product is required to operate stably and accurately.

Solution Advantages:
  1. Provides a variety of product supporting schemes to cope with different working conditions;
  2. Customizable products to cope with complex working conditions;
  3. Excellent product quality, high precision, high stability, and high protection level.

Project Description

I. Typical User Specific Needs

User: Hongshan 6979 Commercial Center

Needs: Hongshan 6979 Commercial Center is one of the landmark buildings in Longhua, Shenzhen.
The Hongshan 6979 Commercial Center has four fire water pools, distributed around the underground parking lot, with a water depth of 6 meters and a distance of approximately 3000-4000 meters from the fire control room. The user now requires that the fire pool should be equipped with on-site water level display devices according to the requirements of the "GB 50974-2014 4.3.9 clause" (see Figure 1) -- and devices displaying the fire water pool water level should also be set up in the fire control center or duty room etc., and there should also be high and low alarm water levels.

Figure 1

II. Schematic Diagram of the Scheme

Design and development of a fire water pool level on-site display device and a dual display solution in the fire control room that meets the requirements of the new fire protection regulations:
1. Use one level sensor probe with two level indicators, one displayed on-site in the user's pump room;
2. Install a 4-20mA remote transmission output module (signal can be transmitted 5000 meters) on the pump room display WH6-T;
3. Transmit the level signal to the WH6-T intelligent level display in the fire control room 4000 meters away, which also has high and low level alarms, completing our "one-to-two" display.
The following diagram of the one-to-two display design institute drawing is for reference.

Figure 2 Design Institute Design Drawings

III. Specific Wiring Scheme Description

1. Place the WH311 fire-proof lightning protection level sensor probe directly into the bottom of the fire water pool;
2. Connect the level probe signal line to the on-site level indicator WH6-T in the pump room via a 2*1.5 square RVVP cable; connect the red wire to terminal 4, and the green wire to terminal 1. Short-circuit terminals 2 and 3 with a short-circuit wire. Terminals 23 and 24 of WH6-T provide 220V power, and the WH6-T's built-in 24V power module will automatically power the WH311 probe. After the wiring is complete, the display screen will show the current fire water level in real time; the user can set the AH high-level alarm value and AL low-level alarm value according to their requirements.
3. Transmit the 4-20mA signal of the pump room display WH6-T output module to the fire control room via a 2*1.5 square RVVP cable. Install another WH6-T fire-dedicated display in the fire control center, connecting the signals of terminals 5 and 6 of the on-site level display output module to terminals 1 and 2 of the fire control room WH6-T display. In this way, the display in the fire control room will also synchronously display the actual water level of the fire water pool in real time, and has an intelligent light column display with percentage.
4. Set the high and low level alarm values. When AL is set to 0.5 meters (this value can be set by oneself), the relay will activate, connecting the alarm (to be provided by the user) and making an audible and visual alarm. This achieves the function of low water level alarm. When AH is set to 4.5 meters (this value can be set by oneself), the relay will activate to achieve high level alarm.
This achieves the user's requirement of displaying the fire water pool level in two places with automatic high and low water level alarm function. The detailed wiring diagram is as follows.