In our system between 15 and 25 PLCs work together to operate an instrument, these PLCs have to exchange some data with each other for safe operation. This data exchange should ideally take place in real time, which is currently the case with us. We are currently using EtherCAT bridges (EL6695) for this purpose. Since the data has to be transferred from one PLC to many, from many to one and from one to the other, we use a hierarchical network structure in which all information has to run through one or three "master" PLCs. Since changes to the data to be exchanged always affect more than a PLC and this usually means a greater effort and intervention in the operation, we would like to use a somewhat more flexible solution here. At the moment it is already the case that we build reserves in all PLCs and do not always have to update with down time, but a structure that would make this superfluous would be desirable. The EtherCAT Automation Protocol would be an alternative that would still be largely deterministic, but on the other hand would mean great flexibility.
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