O lançamento do XP340, CLP com suporte a WebServer, não é a única novidade da linha Nexto Xpress para este final de ano. Além do novo membro, a família de controladores programáveis compactos da Altus também ganhou dois recursos capazes de aumentar ainda mais sua capacidade de alcance. Agora, os equipamentos Xpress contam com desenvolvimento de protocolos de baixo nível and expansão de entradas e saídas via interface CAN.
Xpress solution controllers have a CAN bus interface that is compatible with CAN 2.0A and CAN 2.0B standards – 11- and 29-bit identifiers. There are two more traditional use cases for this interface: with the CANopen Manager protocol, which allows the PLC to communicate with CANopen slave I/O devices, and with the CANopen Slave operating mode, used in applications where the PLC acts as a secondary I/O device. In addition to these two cases, we can also use the interface for low-level CAN communication.
Development of low-level protocols
In order for the exchange of information between the components of a network to occur in an orderly manner, a number of protocols are established that define the rules to be used when communicating between the components. In this case, each subnet interface is responsible for implementing the medium access protocol that controls its transmissions, the link protocol that regulates communication between interfaces, and the network access protocol that specifies and polices the interactions between the interface and its user. These protocols within the scope of the communication subnet are called low-level protocols.
Low-Level CAN Communication allows the PLC to transmit and receive raw CAN messages without using upper layer protocols such as CANopen, which can be useful for communicating with devices that use custom protocols. These features are available in all models of the Nexto Xpress line starting with versions 1.8.5.0 of the firmware and 3.19 of MasterTool IEC XE.
The CANOpen protocol
Created in 1994 by a group of companies, CANOpen is one of the most complete and diversified Industrial Networks on the market today. By operating on a multi-master communication standard, the network meets the needs of markets with the highest complexity and data security requirements, such as the medical, railway and naval navigation segments. Based on CAN Network technology – created in the 1980s for use in embedded systems in trucks, buses and automobiles – the standard presents itself as an open industrial network with moderate cost for complex applications.
The multi-master model used by the standard provides greater agility in communication between application devices and simplifies network work. The modularization of the network also brings benefits in terms of the installation, renovation and implementation of equipment and new field components up to the maximum number of slaves in the ASi Network (31 slaves). In addition, the protocol is standardized in accordance with IEC, ISO and ITU criteria, with its application layer being defined in the EN 50325-4 standard.
How to use I/O expansion via CANopen on Nexto Xpress
To help you with this task, we have created a tutorial explaining how to configure the Nexto Xpress I/O Expansion via CANopen. By accessing it, you will find a step-by-step guide on how to enable the feature in all products in the Altus compact PLC line.
Do you have questions about the feature or need help setting up your expansion? Contact our Technical Support team by calling 0800 510 9500 and our experts will help you!
