On the design of anti-theft alarm system in building intercom system
In the construction of intelligent systems in all communities, the most popular and closely related to the lives of residents should be the building intercom system and the home anti-theft alarm and emergency help system. In the early construction of intelligent communities, since the manufacturers of building intercom systems and anti-theft alarm systems are relatively independent, the system did not consider too much integration. Basically, they used products from multiple manufacturers. A building intercom system with alarm function has been released. Because the alarm system is unique in terms of technical complexity, reliability, operability, and function, how can traditional alarms be designed in a unified manner with the building intercom system, and combined together to be mass-promoted in smart communities Use is the focus of this article.
(1) Introduction of typical alarm system networking methods At present, there are various alarm systems on the market that use telephone lines, buses, networks, power lines, dedicated lines, wireless, etc.
We mainly discuss the two most widely used at present.
1. Telephone line networking mode The alarm host in the home and the management center are networked through ordinary telephone lines. This networking method is used in early intelligent communities. At present, foreign manufacturers such as ADEMCO, C & K, FBI, and DSC all use this method.
advantage:
It is suitable for distributed alarms and requires more financial banks and villas;
No wiring required Because ordinary telephone lines are used for networking, no wiring is required with the management center, which is suitable for the renovation of old communities;
With voice communication alarm function, you can dial mobile phones and phones for voice communication alarm;
Disadvantages:
Small capacity and slow alarm speed. Because the alarm center also uses a telephone line, communication congestion will occur at the same time for multiple alarms. Generally, it will take 8-20 seconds for the alarm to be triggered from the alarm trigger-"Dial-up report-". Taking into account the alarm system every day All have a certain status (disarm, self-test, etc.)
Signal reporting is not suitable for use in large and medium-sized cells.
High communication costs Due to the use of telephone line communication, each communication with the alarm center must pay a telephone fee.
Overview:
The telephone line networked alarm system is more suitable for the requirements of decentralized alarms, and it has the characteristics of voice communication and no wiring.
Especially suitable for the alarm transformation of the old community. However, in a newly built community with a certain scale, the communication speed is slow, the capacity is small, and the cost is high.
The high cost is a shortcoming that affects the promotion and use. At the same time, it is different from the intercom system in the way of networking, and it also cannot be effectively combined with the intercom system.
2. Bus system networking method The alarm host in the family and the management center are networked through a special data line (2-core), each alarm host has an opposite address code, and the alarm situation is identified by the address code. This networking method is more widely used in smart communities. At present, domestic professional bus system alarm hosts and building intercom alarm hosts all use this networking method.
advantage:
The communication speed is fast and the capacity is large. The 485 bus mode is used. When the baud rate is only 2400, it is only 0.1 ~ 0.3 seconds to report a warning message.
The center is basically not busy, suitable for large-capacity residential areas;
The two-way communication method adopts the bus system. Not only the alarm can be reported, but the center can also quickly download information;
Low cost Because the community uses its own communication line, there is no cost for alarm communication, which can reduce the burden of residents;
Good integration performance Because most intelligent systems use bus communication, it is easy to integrate with other systems, reducing engineering costs,
Enhance the center communication control function;
The low-cost bus system alarm system eliminates the dialing module in the telephone line alarm system, and the cost drops a lot, which is convenient for popularization;
Disadvantages:
High engineering construction requirements have high technical requirements for line laying and bus isolation;
No voice communication function is only suitable for network use, not suitable for exclusive use by households, and lacks effective means of alerting users;
Not suitable for long-distance alarm users. The communication distance between the general alarm and the center cannot exceed 1200 meters;
Overview:
The bus-based networked alarm system has the outstanding advantages of fast speed, large capacity, and low cost. Because it can be uniformly wired with the building intercom system, it is very suitable for use in newly built, especially large and medium-sized communities.
(2) Design points of building intercom alarm system At present, there are a variety of building intercom systems with alarm functions on the market. Professional alarm systems start from "Old Wang Xietang Qianyan,
"Flying into the homes of ordinary people" is recognized by ordinary residents and is the result of years of promotion in the field of intelligence. But is it a host with an alarm function that can really meet the alarm requirements of residents? The design of building intercom alarm system, It is necessary to fully consider the different objects of use and different environments of use. In the technical design, we must absorb many important functions of professional alarms to ensure that the alarm system is used in a large number of civilians. It must not be just the functional decoration and sales. Selling point.
1. Reliable communication guarantees that the building intercom alarm module must report the alarm signal to the management center reliably after receiving the alarm signal, and no false alarms, especially missed reports, can occur.
Make sure the alarm is successful.
Does the alarm information confirm whether the alarm part of the building intercom receives the alarm signal and sends it to the management center? The central alarm information confirmation mechanism must be established. After receiving the alarm information, the management center should send a confirmation signal to the alarm host, indicating that the center has received it, and the building intercom alarm host should resend it when it does not receive the confirmation signal;
Alarm information verification Alarm information and building intercom communication information share data lines and network with the management center. Complex line problems and communication conflicts (alarm and building intercom information) may cause alarm information errors. Communication information must be verified (Eg CRC, checksum, etc.)
, The management center verifies the information and retransmits the error;
The communication monitoring alarm information adopts the active sending mode, and the communication line is monitored before sending to avoid the data rear-end phenomenon.
Ensure a successful communication;
2. Rich communication protocol A good alarm host must have a rich and scientific communication protocol. A host that can only communicate with the alarm is still far from practical requirements. For example, the currently popular Ademco4 + 2 and Ademco Contact Id alarm communication protocols are relatively complete and scientific.
But in civil occasions, a lot of communication content can be omitted, but the following items have special significance.
Host disarming function When the household disarms the building intercom alarm, the alarm should report the status to the management center for record, which is of special significance.
Residents using the alarm may cause disputes, for example, when others go out for reasons other than arming the system, resulting in property loss,
The alarm system may be falsely accused of failure and a claim may be made. At this time, the management center may query the user's disarming record to confirm,
There are too many such cases in reality; the management center can also monitor the status of important user hosts in a timely manner,
It is even possible for the management center to take the initiative to withdraw the defense for the residents;
The self-checking alarm system is a product that is "not afraid of 10,000, but afraid of it". It can't be seen at work in normal use, but when there is an alarm,
Make sure the alarm is successful! It is difficult for residents to know whether the alarm is normal or not. The design of the alarm should have a self-checking function, and the self-checking result should be reported to the management center at regular intervals, subject to the monitoring of the management center, and immediate maintenance when a fault occurs;
The center actively withdraws the arming function. What should I do when I live outdoors and forget to arm?
In the case of authorization, the management center can send instructions to arm the resident host to avoid unnecessary losses,
Reduce household troubles;
3. Integrated design with building intercom, alarm host and indoor building intercom host are integrated design, to ensure that the user operation is more convenient and highly integrated,
Engineering construction is also brief. The following items deserve attention in the design.
Modular design Modular design can not only bring convenience to manufacturers, but also very suitable for practical needs. As a basic building block,
Building intercoms are installed in residential homes, usually in one place, and the alarm module is installed according to user requirements.
Modular design can flexibly apply this model, reduce intelligent investment, and the engineering company is willing to accept;
The unified wiring of the building intercom and the alarm system is uniformly wired and connected to the wiring panel of the intercom host of the indoor building of the residents.
From non-visual-"visual-" alarm no need to re-wire, easy to upgrade the system;
One-line design building intercom and alarm systems can share the same data line (two-core 485 bus), reducing the amount of wiring and facilitating central system integration.
However, it is necessary to satisfactorily solve the problem of conflicts caused by the intercommunication of a large number of building intercom messages and alarm messages on the same line.
A reasonable communication protocol must be formulated uniformly (see previous section);
Humanized operation design The daily operation of the alarm system (removal of arming, emergency alarm, etc.) should be oriented to users at all levels. For example, try to use key operation,
There must be clear indicator lights and horn tips, use the remote control when possible, and concentrate daily operations on the remote control,
The alarm panel is completely transparent to users.
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