Application of PLC in fire pump

At present, high-rise buildings abound in various cities. In order to prevent accidental fire, high-rise buildings are generally equipped with fire pump. Although norms, rules and regulations clearly require fire-fighting facilities, equipment should be regularly maintained. However, the current fire pump can not do regular test run, over time will lead to the pump, the end of the valve and one-way valve stuck dead rust, it often appears in the event of a fire equipment can not fully play the role of the situation, resulting in not Due to the loss, for this "civil building water fire extinguishing system design rules" provides for high buildings, a class of high-rise public buildings fire pump should set the self-test device. National Fire Services Department in 1999 below requires that all fire-fighting equipment must have a self-test function, fire control equipment must be automatically activated within 15 days once to prevent corrosion of the pump rust. Another revision in the "Code for Fire Protection of Buildings" also proposed: fire water supply equipment must have automatic inspection function. Usually the old equipment adopts the backward relay contactor control mode, the intermediate relay and the timing relay are too many, the function is less, the line is complicated, the contact is many, cause the trouble more reliability is bad, the maintenance is difficult. We use Beijing Kaidian Automation Technology Co., Ltd. programmable logic controller (PLC) to control the fire pump group, the pump group to achieve regular trial run standby, fire fighting automatically start, so as to effectively eliminate the fire pump can not be the key moment Used situation. The reason why PLC has vitality lies in its input and output terminals are closer to the field devices, without adding too many intermediate components or need more interfaces, high reliability, anti-interference ability, easy maintenance, no hardware adjustments Components, low price and long life. This saves users time and costs, but also can easily be expanded according to different needs.

1, automatic inspection function

Under automatic condition (inspection switch is on), the first pump starts (star) for 5-30 seconds under the condition that there is no need for fire fighting water (starting time is determined according to the equipment). After running (triangle) for 10 seconds, -360 hours (five to fifteen days). If there is no fire fighting water on standby, the second pump starts 5-30 seconds, runs for 10 seconds and stands on standby for 120-360 hours, so that it cycles cyclically (inspection cycle: from hours to hundreds of hours Select) control cabinet and with overpressure protection, from a reliable point of view, to set the pressure relief valve. In the fire water demand, the pump immediately start automatically, pressurized water supply, give full play to its role. If in order to avoid damage to the pipe network due to pressure increase, we increase the electromagnetic valve in the pipe network, open the electromagnetic valve to check the pump pressure relief, inspection pump start working time is also delayed to 10 minutes.

2, Kai pump way and order

In the case of automatic start of multiple pumps, in order to avoid the simultaneous introduction of the pump caused too much impact on the power grid, the pump is a station 20 seconds apart from the start. Automatically start and patrol Kai pump, first issued three sound and light alarm (alarm 2 seconds interval 2 seconds), and then start the pump. The backup pump should be able to be put into operation automatically (with a delay of 10 seconds) when there is a malfunction in the working pump of the device (overload and short-circuit signals) because of the importance of the fire pump The backup pump is operated without overload protection. Starting pump frequency direct start, start from the lotus buck, Y- â–³ buck start, thyristor soft-start control, constant frequency control and other means to meet different requirements. For example: 2 pump start sequence 1 with 2 standby, 2 with 1 standby, two ways; 3 pump start sequence 1,2 with 3 backup, 2, 3 with 1 backup, 3,1 with 2 prepared, three ways and so on.

3, control panel display

In the design of automatic control system, we designed the fault display alarm system. When the device starts up, the indicator blinks at a frequency of 1 Hz. The corresponding indicator light is on in normal operation. The fault indicator is always on when the device is faulty. In order to prevent the lamp bulb damage can not correctly reflect the work of equipment, specially set the fault test button, the system is running at any time press any button 3s, all the lights should be all lit, if there are instructions, etc. do not light at that time that the light Has been bad, should be replaced immediately, the button is still reset after the indicator shows the working status of the device.

4, fault display

When the device fails, the signal box will use sound, light alarm prompts staff, timely troubleshooting. In dealing with the fault, but also the classification of the fault, some faults require the system to stop running, but some faults have little effect on the system work, the system can run with faults, the fault can be excluded in operation, thus greatly reducing the entire system to stop Running time, improve system reliability level of operation.

5, the interface circuit

In order to support the equipment manufacturers, the control cabinet has two sets of pump mode: 1. A pump signal and a stop pump signal is generally used for multi-line manual fire control center or automatic control, can also be used for low pressure pump, super Pressure shortage of water stop pump. 2. A signal, connected to open the pump off pump, generally used for module control. In order to match the fire hydrant button to pump directly, the cabinet provides 24V5A DC power supply all the way.

Interface circuit is all DC 24V power supply, the module can be directly controlled by passive contacts, switching module does not need to switch, but the control signal must be passive contact signal. Pump feedback signal is a passive contact signal.

6, protection function

Electric control cabinet with overvoltage, undervoltage, overcurrent, short circuit, lack of phase, water shortage and other fault alarm and protection functions. In the fire water to avoid frequent over-pressure water pressure fluctuations caused the pump to stop, we used in the program "delay filter" treatment.

7, other functions

In the automatic manual switching process will stop all running pumps; According to user needs to install dual power switching function, or with a separate dual power inter-cabinet, the main, backup power can be automatically or manually switch to meet the fire protection system Design requirements. Equipment can also be based on user requirements additional building automation (BA) interface, and terminal computer networking, centralized computer monitoring.

The system uses programmable logic controller for control system design, hardware structure is simple, low cost, fast response, high performance, high price ratio, and single-chip microcomputer system compared with high reliability. The field test, stable performance, reliable operation. In addition, according to actual needs can be easily expanded. For modern intelligent buildings, the control system can also be integrated into the monitoring system of the entire building through the communication module, which shows great flexibility and adaptability and has very high practical promotion value.

Non-standard Mold Base

OEM High Precision Non-standard Parts Manufacturers Customized Mould Base