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EtherCAT Diagnostics

The EtherCATEtherCAT is an open, high-performance Ethernet-based fieldbus system. The development goal of EtherCAT was to apply Ethernet to automation applications which require short data update times (also called cycle times) with low communication jitter (for synchronization purposes) and low hardware costs nodes provide several types of diagnostic information through various registers. The KAS controller uses these diagnostic registers to detect error conditions in the EtherCAT network. This can include:

Physical Link status	Indicates if a hardware connection between two nodes is established.
Link Lost Counter	Indicates how many connection lost events have occurred between two nodes. Some EtherCAT devices will not detect the lost link event.
Rx Error Counter	This counter is incremented when the node detects any signal error detected by the hardware.
Rx Invalid Frame Counter	Invalid frame error is detected when the CRC"Cyclic redundancy check" A CRC is a type of function that takes as input a data stream of any length and produces as output a value of a certain fixed size. The term CRC is often used to denote either the function or the function's output. A CRC can be used as a checksum to detect accidental alteration of data during transmission or storage (Cyclic Redundancy Check) does not match the received frame CRC.
Forwarded Rx Error Counter	FrameIn networking dialect, a message is called a frame error detected by the previous node and forwarded to this node.
EtherCAT Processing Unit Error Counter	Counts errors in the EtherCAT frames such as frame length or a non-EtherCAT frame. Not all EtherCAT devices support this register.

Application Started: When the application is started, the KAS controller resets the Link Lost Counter, Rx Error Counter, Rx Invalid Frame Counter, Forwarded Rx Error Counter, and EtherCAT Processing Unit Error Counter registers of all the nodes.
Application Running: While the application is running, the KAS controller monitors every cyclic frame and detects any missing or invalid frames. If any frame is missed or invalid, it generates an A38 alarm.
Application Stopped:When the application is stopped, the controller will read the EtherCAT node diagnostic registers and process them. If any error condition is detected, an EtherCAT diagnostic log message is generated. The log messages can be used to identify the location of the communication failure.

The PAC"Programmable Automation Controller" PAC is a compact controller that combines the features and capabilities of a PC-based control system with that of a typical programmable logic controller (PLC). A PAC thus provides not only the reliability of a PLC, but also the task flexibility and computing power of a PC. Additionally, because they function and communicate over popular network interface protocols, PACs are able to transfer data from the machines they control to other machines and components in a networked control system controller does not check the EtherCAT diagnostic registers.

The node register of Link Lost Counter, Rx Error Counter, Rx Invalid Frame Counter, Forwarded Rx Error Counter, and EtherCAT Processing Unit Error Counter will have non-zero values when a cable disconnection or an EtherCAT frame corruption occurs, The following example indicates that a communication failure occurred between Node 0 and Node 1.

EtherCAT   | WARNING | EtherCAT diagnostics: Node 0, port B (out), Rx Invalid Frame Counter Register is 255

EtherCAT   | WARNING | EtherCAT diagnostics: Node 1, port A (in), Rx Invalid Frame Counter Register is 255