Flex I/O (Ethernet/IP)

[DLite]

I recently did a project that replaced some ControlNET and DeviceNET FlexIO modules with Ethernet (1794-AENT). The connection time from power up went from a few seconds on ControlNET to 30-45 seconds with the Ethernet. Has everyone else seen this same connection time?

On a power-up that's a typical boot time for a Flex AENT module.

 

[Archie]

On a power-up that's a typical boot time for a Flex AENT module.

This came as a surprise to me. There is this common perception that Ethernet is very fast. So then why does it take so long to establish a connection? Even if you allow 5 seconds boot up, that leaves at least 25 more seconds before the connection is established.

To put that in perspective, let's say a packet of 100 bytes is exchanged every 50ms (which is very conservative, 20ms is more realistic). That means 2000 bytes per second and 50Kb can be easily exchanged over the 25 second span. It only takes a few hundred bytes to establish a class 1 CIP connection. What really is that FlexIO module doing all that time? Just my opinion, but the Point IO has a huge advantage because it connects much faster.