Omron PLC Center

DeviceNet has become one of the most supported control networks. This is an open standard, so components from a variety of manufacturers may, in the same system of control to be used. It is supported and funded by the Open DeviceNet Vendors Association (ODVA) (see http://www.odva.org). This group includes members from all major manufacturers of controls.

This network was designed so that noise resistant and robust. An important change for the control engineer is that the PLC chassis can be eliminated and the network can be directly connected to sensors and actuators. This will reduce the total amount of wiring by using I / O points closer to the point of application. This can also simplify the connection of complex devices such as HMI. Two inputs and outputs of the two-way communication allows for a diagnosis of network problems from the main controller.

DeviceNet covers all seven layers of OSI standard. The protocol has a limited number of network addresses, with very small data packets. But it also helps to limit network traffic and ensure responsiveness. The length of network cable, the maximum speed of the network. The key features are listed below.

· A bus cable carries data and power transmission.

· Up to 64 nodes in the network.

· Size of the packets of 0-8 bytes.

· Length 500m/250m/100m or 125kbps/250kbps/500kbps for the speed.

· Devices can be added / removed while the device is switched on.

• Based on the CAN bus (Controller Area Network) protocol for OSI layers 1 and 2

· Covered are peer-to-peer, multicast, master / slave, polling or change in condition.

An example of a DeviceNet network is a DeviceNet network lake appears. The blacks are dark lines on a network cable. Terminators at both ends of network cable is needed to reduce electrical interference. In this case, the PC probably run some kind of software based PLC program. The computer should have a card that can communicate with DeviceNet devices. The rack-Flex is a mini-rack, that different forms of input may hold or exit. Taps Power Tees (o) split the signal side branches. In this case, the valves will connect an AC adapter to supply the 24V DC supply to the network. Two other valves are used to connect a smart sensor in conjunction with, and another frame flex. The Intelligent Sensor uses the power of the network and contains enough logic so that it is a node of the network. The network used to restrict thin and thick trunk line trunk line, the network performance.

Share This