Scalance Vs Stratix

Hi Everyone,

I'm currently working on some OT network upgrades for my company across two sites. Painfully, the two sites have gone in different directions on the PLC side of things. One is standardized on Rockwell and the other has standardized on Siemens. (all occurred well before my time with the company).

For selection of Switches for these upgrade I am faced with a couple of options. I was hoping for some opinions on which approach to take here.

Option 1: Select one range of switch and standardize across both sites.
Option 2: Install the Scalance Range on the Siemens site and Stratix Range on the Rockwell site.

(I understand there are other switch vendors, however I would like to stick with either Siemens or Rockwell)

Can anyone offer any advise on which way they would go and why?

We are designing based on the Purdue Model and aiming for a fault tolerance of 1, most likely deploying ring topologies at both sites.

TIA

Jayden

This year, your selection might want to start with "Who can get me the switches I want this year"? Things are bonkers right now. I assume both are currently bad, but your experience may vary.



How much management do you plan to do in the switches? If the goal is a switch that can be dropped in with minimal fuss, the Siemens Scalance line (at least the recent generation of switches) has available defaults optimized for Profinet or EIP. Some models have part numbers to default to one or the other, but both models can configured to either. It's often very nice to be able to grab a managed switch, slap it in a panel, and then kinda treat it like its unmanaged, while still getting the benefits of the diagnostics, etc.



On the Siemens side, if you use a switch that can be a PN device, switch status things like missing cables can be reported automatically to the PLC, which will then send it to the HMI. Scalance definitely supports this; I assume Stratix would as well, but dunno.



If you're looking for an OT focused NMS solution, there is a product called SINEC NMS from the SCALANCE group that can do both monitoring and configuration, although I've never used it, only the prior version.



The Scalance switches have a CLI that I've seen network professionals use, but controls engineers are usually very happy to use the web interface for configuration. You can ALSO configure them in TIA Portal, and download to them like you would a drive or PLC, but I haven't really gone down that path before.



I have limited experience with Stratix, most of my experience is on the Siemens side. From what I've seen, the Stratix Web interfaces are super clunky (possibly they've been improved since), because they come from Cisco who assumes that real work will be done on the CLI. Not sure where your preference is. For Profinet use, there's a telecommunication option you usually need to enable on Cisco devices, before the VLAN 0 priority tags in Profinet will work properly (or sometimes frames get blocked entirely).

Regarding the ring topologies, I'm not aware of any Scalance support for DLR with EIP, but that may have changed with FW updates since I last looked. They support MRP for Profinet IO. They also have modules that support HSR. I'm sure both Scalance and Stratix support Rapid spanning tree, but in my experience that isn't usually suitable for the control level, possibly at the plant level.


I've never met anyone who was happy using Stratix in a Siemens system. I have seen people happy using Scalance in an AB system. Most people either use what matches the PLC or use a 3rd party (Moxa, Phoenix contact, etc) for everything.