Keywords:fire-fighting system,PLC multi-network communication
With the development of economy, more and more buildings in the city.Prevention and fire extinction is very important. Fire self-control system is to prevent and put out fire.This fire extinction system can put out fire automatically in the early stage.When the fire occurs, alarm system send out fire signal and notify fire control system.Then fire control system will put out the fire. Here we make an introduction of fire self-control system.
1. This system is used in the fire-fighting system for a large building. The system has 43 fire equipment and located in different places of the building. The distance between these two devices is distant(tens of meters to hundreds of meters). Now we need to communicate these 43 devices for central monitoring.
2. In order to ensure the reliability of work, the center can monitor every device within the scene.It can send fire signal to related equipment from time to time and control corresponding device to put out the fire. At the same time also requires on-site equipment can not only control the center to the scene but also on-site control.
3. To view the status of the fire scene at first time, you need to send the scene video to control room to facilitate inspection of fire and putting out fire.
4. When central operation operate a device, also need to switch to the current operating equipment video to realize manual control.
5. When a communication failure between device and central network, the center and the scene should alarm at the same time.
6. In order to ensure the stability of the controlling center, there must be more than two operating systems.
7. The real-time data communications and stability between control center and 43 equipmens, and reliability must be guaranteed.
8. Economic and operational is also an important factor in the actual operation.
1, Communicating these 43 sets of fire equipment to realize central remote control. Taking cost, wiring and construction of convenience into account, we will use RS-485 network. Because RS-485 only need to pull two lines, wiring convenience and cost is low.The network span distance is as long as 1 km. At the same time,considering the large amount of network communication ,large quantities, switching and digital value also on-site analog,single communication port’s real-time communication is not enough.Then we decide to use three RS-485 for communication. It not only solve large amount of data and real-time communication problems, but also improve the reliability of work. Bringing inconvenience of wiring, you can pave more network line.
1. On-site PLC control a variety of action of single fire fighting equipment. The center control every single equipment through on-site network.Controlling program is in a single device, while communication control program is in central PLC.
2. When the central operate any equipment or the fire alarm signal from any equipment,the system should be able to see the first scene through video.So we add one video in the center to view scene of fire situation. Because each device has a video, so add a video matrix for 43-way video switching. When the fire happen or any equipment be controlled,you can switch to the video of equipment you want automatically.
3. When network is broken, the scene and center must all alarm together. Central fault alarm: the usage of Haiwell PLC simple communication instructions.Only one instruction can finish each station address communication.Also it has marked flag to indicate whether communication is succeed or not.We can make this marked flag as central communication failure alarm to make center and scene achieve effective alarm .On-site network fault alarm: When communication with center is normal, the center will always set "ON" to the local M bit. The local program will be on the M position "OFF" for a period of time.If this M-position are not "ON" for a long time,it imply communication with the central fault.You can use this M-position to judge whether the communication between scene and center is successful or not then to send network failure alarm.
4. Center is an important controlling point.There must be two or more sets of control mode. Use computer and touch screen to control the center to increase the controlling reliability. These two are independent and control the same center at the same time. When one is failure, the other one will control the system.So it will not affect normal work of the center to achieve reliable controlling.
Above all , fire system network as below:
1. COM1 and COM2 are the communication ports of the PLC itself. COM1 port (RS-232) is connected to the host computer and COM2 (RS-485) port is used for central touch panel. Three extended communication ports (COM3, COM4 and COM5) are also provided for the networking of 43 fire fighting equipment. Each communication port of Haiwell PLC can upload and download program and for communication.Also support for parallel execution to ensure real-time communication.
2. The DI module is used to transmit the fire alarm signal to the center.The center will transmit signal to corresponding fire equipment according to the processed fire alarm signal and generate fire alarm indication.Send current outputted fire area is to the video matrix by DO module. and switch the current fire video in the video TV through video matrix.
1.Program capacity: 16K
2.Extended communication port: 3 extended communications up to 5 communication ports. Each communication supports parallel work and can download or upload program or for communication.
3.More control points: a host can be extended to 7 modules
4.Simple communication command : one command complete one device.No need of manually control timing sequence to prevent communication conflicts.It have signal for communication is succeed or not. It make debugging work for technical staff easy and improve working efficiency.
5.High communication efficiency: communication program has nothing to do with the scan cycle.Communication programs and other programs execute in different CPU execution.It ensure the real-time communication.
Haiwell powerful communication ability,no-interval communication implementation and easy communication instructions make this large network easily. It can also be achieved by RS-485 network.This reduces cost and ensures real-time and reliable communication.