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Hardware Diagnostics for Master/Slaves (EtherCAT)

Hardware errors include the permanent or temporary interruption of the transmission medium (damaged cables, loose contacts, etc.) or unexpected changes in the network topology (e.g. due to the reset of a slave), as a result of which the EtherCAT frames either do not reach all slaves or cannot be sent back to the master by them. Furthermore, defective slave devices or EMC interference can cause frames to reach all slaves in the network and return to the master, but contain faulty bit sequences after transmission.

For hardware diagnostics, status displays on the device and frame counters in the software are available.

This topic contains the following sections:

Evaluating the Link/Activity LED on the Device

Most EtherCAT slaves have a Link/Activity LED on the RJ45 port. If necessary, check this LED before reading out 'Lost link' or other counter values. If the LED is off (although the slaves involved are supplied with power), there is a possibility of an interruption or damage to the Ethernet cable.

Evaluating the status indication LED of the bus interface on the Device

Connection and configuration errors can not only be detected using diagnostic variables or objects, but are usually also displayed via the status LED on the device.
You can find out how to interpret the LED displays in the Technical Manual for the device. There you will find detailed descriptions of all LEDs.

Hardware Diagnosis by Counter Evaluation

Using various counters provided from the master and the slaves in the 'Online Functions' editors, the EtherCAT communication can be monitored and evaluated:

The 'Lost frames' counter, for example, counts data frames (in cyclic communication) that either do not return to the master at all or are damaged. This counter can therefore be seen as a first indication of communication problems at hardware level. From the slaves, the counter values 'Invalid Frame', 'Lost Link' and further error counters are provided.

The following counters can be used for diagnostic purposes: