If you have set up your EtherCAT network in a daisy-chain like fashion, once you disconnect or power off a slave, the remaining ones in-line go offline. This article describes how to remedy this issue.
APPLICABLE PRODUCTS
All products with an EtherCAT slave interface
QUESTION
How to mitigate daisy-chained EtherCAT slaves going offline downstream a disconnected slave?
ANSWER
EtherCAT can address up to the theoretical limit of 65535 slaves, regardless of the topology, with no impact on performance. So you could connect that many devices in a line topology.
However, once you power-off or disconnect a single one, the remaining downstream devices will no more be reached by frames. Therefore, you should shift over to using a ring topology.
Alternatively, if you require slaves or groups of slaves to be powered off or disconnected independently from the rest of the network, you should consider a star topology.
ADDITIONAL INFO (Optional)
EtherCAT Installation Guideline, Document ETG.1600, (Guideline for Planning, Assembling and Commissioning of EtherCAT Networks)
