[etherlab-dev] Slave to Slave communication

[PAUL-SOFTWARE]

Thanks!
I find your information helpful!


-----Ursprüngliche Nachricht-----
Von: etherlab-dev [mailto:etherlab-dev-bounces at etherlab.org] Im Auftrag von Dave Page
Gesendet: Montag, 11. Mai 2015 12:23
An: etherlab-dev at etherlab.org
Betreff: Re: [etherlab-dev] Slave to Slave communication



On 2015-05-11 22:00, etherlab-dev-request at etherlab.org wrote:
> Have anyone ever run a Safety-over-Ethercat solution via the etherlab-master?

     I have successfully used the EL6900 FSoE PLC, EL1904, and EL2904 via the IgH master. It is necessary to use TwinCAT to program the PLC initially, and to identify all the PDO data which must be coped.

     There is nothing fundamentally difficult about FSoE, except understanding how all the pieces fit together is not easy. Suggest reading the FSoE specification (ETG5100) first for an overview. The specification does not disclose anything about the specific EL6900 implementation in terms of how to burn your PLC code onto the EL6900 -- this is a black box for which TwinCAT is mandatory.

     In every cycle of the domain, the application (your code) must copy short byte arrays of data from the PLC TxPDO to each FSoE slave, and from each FSoE slave to the PLC. This is easy to arrange with, for example, memcpy(). The use of fancy datagram commands like FRMW or overlapped mapping of the PDOs in logical space is not at all useful with regards to FSoE -- the data movement is simply copying bits between ordinarily mapped PDOs in the application software and nothing more. The protocol is designed to accept multiple process data cycles of latency between updates, as the fault condition is detected using a watchdog timer.

         Best regards - Dave