Zigbee is a wireless data transmission network platform composed of up to 65,000 wireless data transmission modules. It is very similar to the existing mobile communication CDMA network or GSM network. Each Zigbee network data transmission module is similar to a base station of a mobile network. Within the entire network, they can communicate with each other; the distance between each network node can range from the standard 75 meters to the extended hundreds of meters, or even several kilometers; in addition, the entire Zigbee network can not only be extended "infinitely" Open, but also can be connected with various other existing networks.
ZigBee adopts a self-organizing network method, with a coordinator as the core (mainly playing the role of building a network and a central node), and other nodes freely join the network built by it. The default group is a mesh network, which has strong self-healing and network capacity Large, such as F8913D ZigBee module or F8914-E ZigBee terminal, which can realize communication between 100-255 nodes at most. The farthest transmission distance can reach 2KM (open seaside and unobstructed environment), and it can reach 600-800 meters in the test on a straight highway.
Each Zigbee network node (FFD and RFD) can support up to 31 sensors and controlled devices, and each sensor and controlled device can eventually have 8 different interface modes. It can collect and transmit digital and analog quantities.
ZigBee is a low-power local area network protocol based on the IEEE802.15.4 standard. According to international standards, ZigBee technology is a short-distance, low-power wireless communication technology. The advantage of its wide application in industry is that it can freely form a network without incurring operating expenses. But because it uses 2. 4G high frequency transmission, its penetration and transmission distance are restricted. The actual transmission distance is tens of meters to hundreds of meters.
Low power consumption
Due to the low transmission rate of ZigBee, the transmission power is only 1mW, and the sleep mode is adopted, and the power consumption is low, so ZigBee devices are very power-saving. It is estimated that in the low-power standby mode, ZigBee devices can last for 6 months to 2 years or even longer with only two AA batteries. This is the outstanding advantage of ZigBee. In contrast, Bluetooth can work for several weeks and WiFi can work for several hours; this is beyond the reach of other wireless devices.
low cost
By greatly simplifying the protocol, the cost is very low (less than 1/10 of Bluetooth), and the requirements for the communication controller are reduced. According to predictive analysis and calculated with an 8051 8-bit microcontroller, a full-featured master node requires 32KB code. Function nodes are as few as 4KB of code. The initial cost of the ZigBee module is about US$6, and it is estimated that it will soon be reduced to US$1.5-2.5. The ZigBee protocol also uses patent-free technology wisely. Low cost is also a key factor for ZigBee.
Short delay
ZigBee's response speed is relatively fast, the communication delay and the delay of activation from the sleep state are very short. The typical search device delay is 30ms, and generally it only takes 15ms to switch from sleep to working state. The channel access delay of the active device is 15ms, further saving power. In comparison, Bluetooth takes 3-10s, and WiFi takes 3s. The device activates quickly, and the message confirmation in the on-demand is at the microsecond level. Therefore, ZigBee technology is suitable for wireless control (such as industrial control occasions, etc.) applications with demanding delay requirements.
Large network capacity
ZigBee can adopt star-shaped, sheet-shaped and mesh network structures. A master node manages several sub-nodes. A star-shaped Zigbee network can accommodate up to 254 slave devices and one master device, and up to 100 can exist simultaneously in an area. A ZigBee network, and the network composition is flexible. At the same time, the master node can also be managed by the upper network node and there can be up to 65,000 nodes connected in a network.
The actual network built by CC2530 can basically reach 100 nodes. The "Green Field Thousand Pass" project successfully deployed 1,000 nodes.
reliable
A collision avoidance strategy is adopted, and a dedicated time slot is reserved for communication services that require a fixed bandwidth to avoid contention and conflicts in sending data. The MAC layer adopts a fully confirmed data transmission mode, and each data packet sent must wait for the receiver's confirmation information. If there is a problem during transmission, it can be retransmitted. CSMA-CA, verification and automatic routing repair all ensure that zigbee's wireless communication is relatively reliable.
Safety
ZigBee provides a data packet integrity check function based on cyclic residual check (CRC), supports authentication and authentication, and uses an AES-128 encryption algorithm. Each application can flexibly determine its security attributes.
Self-organization and self-healing
The coordinator automatically establishes the network, and the network can repair itself when there is a node failure.
Dongguan Guancheng Precision Plastic Manufacturing Co., Ltd. , https://www.dpowergo.com