EPOS4: Is Ethernet possible by the RJ45 connectors?

Topic:

• Can the EPOS4 or IDX be commanded by Ethernet?
  Quick answer: No
• What is the difference in between Ethernet and EtherCAT?
• Can the "EPOS Command Library" command the EPOS4 or IDX  by Ethernet or EtherCAT?
  Quick answer: No

Solution:

The RJ45 connectors of the "EPOS4 50/5", "EPOS4 70/15" and "EPOS4 ... Compact EtherCAT" product types are for data exchange based on the EtherCAT protocol only, i.e. there is a need for a master (e.g. Beckhoff TwinCAT, maxon MasterMACS) which commands the EPOS4 by EtherCAT.

EtherCAT is a bus protocol, which has been designed for an extreme fast, so-called real-time data exchange. EtherCAT is typically in use in machines to connect multiple drives and process some coordinated or synchronized motion by a master. 

Important remark:

In case of an "EPOS4 50/5" and "EPOS4 70/15" there has to be the "EPOS4 EtherCAT Card" (P/N: 581245) internally plugged in if EtherCAT data exchange is required. Otherwise the RJ connectors will be without any functionality.

Technical background:

EtherCAT and Ethernet is not(!) the same. EtherCAT is a real-time protocol, which is based on Ethernet, but has been specially designed for industrial automation by the company Beckhoff. In the meanwhile the EtherCAT user organization takes care of the EtherCAT standard. 

An in-depth, very good explanation of EtherCAT basics can be found by the following 3rd party link:
-> https://realpars.com/ethercat/ 

The main technical differences between EtherCAT and Ethernet are well summarized on the website of  www.quora.com as follows:

EtherCAT is built on the first two layers of the Ethernet protocol, as we described in this section. So there are very strong similarities at the lowest levels - but not at the network, transport, or application levels, so there is no TCP/IP or UDP in EtherCAT. EtherCAT has been optimized as a real-time, deterministic master/slave system. EtherCAT frames (messages) are built inside of standard Ethernet Frames. However, there are many big differences, too:

• On an EtherCAT network, only the master can send messages, directing them to the appropriate slaves, and then getting the time-stamped data back from them. This is very different from an ethernet network where every device can send messages, and data is not time-stamped in a deterministic way.
  

• EtherCAT is deterministic, meaning that extremely very low latency real-time data comes back to the master from the slaves.
  

• In an EtherCAT network, the master is in charge of time-aligning all the slaves upon start-up and at intervals, in order to facilitate low-latency time-stamping. This is built into EtherCAT, but must be added to a standard Ethernet network.
  

• EtherCAT was designed from the ground up to allow real-time control over devices and systems with extremely low latency. Ethernet was designed primarily for office applications and interconnecting computers, printers, and other network peripherals.
  

• Unlike a standard Ethernet network, in an EtherCAT network data collisions are not possible because of the restrictions mentioned above.
  

• Data transmission on an EtherCAT network is faster than a standard Ethernet network: 100 Mb/s in effect with very low jitter.
  

• Like Ethernet, EtherCAT networks can be arranged in a wide variety of topologies: line, ring, star, etc.
  

Additional remark:

Not all PC Ethernet adapters and chip sets are compatible with EtherCAT and will work reliable in case of EtherCAT data exchange. Please find a list of approved Ethernet chip sets by Beckhoff's website:

-> Supported network controllers 

EPOS4 / IDX in practice?

The EPOS4 (resp. IDX) offers EtherCAT communication (based on the "CoE - CANopen over EtherCAT" protocol), but cannot(!) be controlled or configured just by Ethernet. 

• In case of "EPOS Studio" it is possible to configure and test the EPOS4 and IDX by EtherCAT. 
  • The EPOS4 (with integrated EtherCAT hardware) must be connected via its RJ45 connector to a separate PC Ethernet interface (or USB/Ethernet gateway). 
  • The integration of the EPOS4 into a mixed (resp. "office") PC's Ethernet network installation is not possible. 
  • "EPOS Studio" has an integrated quite limited EtherCAT master software to exchange data with the EPOS4 by the EtherCAT protocol (CoE).
    
    
• The "EPOS Command Library" does not(!) support EtherCAT, i.e. the "EPOS Command Library" cannot command the EPOS4 (resp. IDX) by EtherCAT and the RJ45 connector.
  • The EPOS4 / IDX cannot be commanded by some PC application code and Ethernet only.

Conclusion:

The EtherCAT interface (and its connector) is intended exclusively for real-time masters (e.g. PLCs) which command the EPOS4 resp. IDX based on the EtherCAT protocol ("CoE - CANopen over EtherCAT").