I'm trying to configure an S7-1512R system.  I thought I'd got everything fixed but I cannot get rid of some hardware compilation warnings and cannot find enough info in the manuals to work out why and whether it's a serious problem or not.

The warnings are "[network item] in [MRP domain] does not support an H-Sync forwarding rule."  These are output for an IO device and a switch in the MRP ring even though those devices support MRP.  From what I understand this forwarding is about reducing network traffic beyond the ring so it won't make a blind bit of difference for the IO_Main device since all it's ports are ring ports anyway.  But is the SCALANCE_Sw going to be sending all the H-Sync frames out to the non-ring ports, and what extra functionality/different type does that switch need to prevent this?

IO_Main is an IM 155-6 PN ST, 6ES7 155-6AU01-0BN0

SCALANCE_Sw is an X206-1, 6ES7 155-6AU01-0BN0

Thanks in anticipation

James

Hello James

I've seen those parts of the manual and indeed replacing the X208 with an XC208 removes the warning when the project is compiled.

BUT...they're only warnings, not errors, suggesting that the TIA compiler thinks the system will work but may not be optimal.  That doesn't fit with 'mandatory'.

From a networking point of view, a protocol is just data within an ethernet frame.  Any switch will forward such a frame to its destination.  If it's a broadcast or multicast address then a switch will send it to more than one port.  The 1500RH manual says switches that support H-Sync forwarding will only send it to ports in the ring, thus avoiding sending it outside to devices that are not in the ring, and so avoid unnecessary network load and prevents interference with OTHER R-systems.

With a closed ring issues arise because frames will be sent both ways round the ring because both ports on any device in the ring can reach the destination MAC address.  Hence you need some manager device to break the ring.  In a 1500R system that's done by the CPUs using MRP.  One of them will set it's ring port to blocking.  The two CPUs will exchange H-sync frames directly between themselves on the cable with no other devices, and as well send them round the ring.  So long as all devices in the ring send those frames forward they'll reach the other CPU so I see no need for the other devices to 'understand' H-sync, just to forward it like any other frame.

And the 1500RH manual goes on to say in a note: If failure of [the direct cable] is unlikely, you can use PROFINET devices without H-Sync Forwarding in the ring.

Has anyone out there actually setup a ring using an X208 switch (or another that doesn't have explicit H-Sync support) and found out whether it works or not?

James