Hi,
Given a standard cyclic process running (PDO exchanges occurring but no other queued SDOs etc), what would be the expected latency of an SDO or VoE transfer (separately both out to a slave and back, ignoring the processing time within the slave itself)? I'm in the process of developing a custom slave (for a custom master app) and am trying to decide whether a particular kind of data transfer (asynchronous and acyclic, but still with a performance deadline, albeit one about 20x more relaxed than for PDO transfers) is achievable with SDO/VoE transfers or whether I would have to reserve PDO space for it (even though most of it would go unused most of the time). I'd prefer SDO, given that it's more standardised, but I don't think it'd work without support for complete access for both read and write, and it looks like for some reason Etherlab does not support complete access reads at present. Or to rephrase the question a bit: 1. If an SDO/VoE request is queued by the realtime cyclic thread, how many cycles will (typically and worst case, ignoring slave failure) run before the request is completed (received and acked but not replied to by the slave), and conversely how many cycles would it take for a message posted by the slave to get into the master and acknowledged? 2. Does this change if the request is queued by a different thread? (And is this even allowed? From what I can tell it looks like most such operations should be cross-thread-safe, but it'd be good to get confirmation.) Regards, Gavin Lambert
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