Hello everybody, what would be the best method to connect a redundant GW setup to a pair of siemens redundant S7-1500R?
I’ve seen a few posts where people configured 3 plc connections (PLC_MASTER, PLC1 and PLC2) and wrote a script that detects a loss of communication with PLC1 or PLC2 and change the IP adress of PLC_MASTER.
I am also thinking of adding a third party OPC server like Kepware on each GW PC.
Other option… WinCC 
I would appreciate hearing your opinion and thoughts on this
Thanks!!
For the S7-1500, I believe the recommendation is to use on the onboard OPC UA server (and connect Ignition as a UA client), rather than the direct Siemens driver.
If you do set up a UA connection, then you can set a ‘Failover’ URL in the advanced properties, which would give Ignition access to both PLCs automatically:
https://docs.inductiveautomation.com/display/DOC81/OPC+UA+Client+Connection+Settings#OPCUAClientConnectionSettings-FailoverVersusBackupPropertiesFailoverVersusBackup
It seems from this post that the S7-1500 redundant models do not support OPC UA client or server functionality.
If that is the case you will have to apply one of the scripting hacks to change IP address manually or use another server like Kepware that may have some kind of device-level redundancy support.
I'm working through the same thing right now, a redundant PLC pair to Ignition.
Siemens has the Simatic NET software, as part of their "SIMATIC_NET_PC_Software_V18" package, which will convert optomized AND unoptomized blocks to OPC UA, and connects to the "system IP" option that lets you use a single IP to connect to BOTH the primary AND redundant PLC.
Just so everyone is aware, V19 of Siemens TIA adds OPC UA to the redundant 1500 series - https://support.industry.siemens.com/cs/document/109824627/new-firmware-version-v3-1-for-simatic-s7-1500-r-h-cpus