Make PCS 7 Stations Visible Through the Terminal Bus

When SIMATIC Shell discovers PCS 7 stations over the management NIC but not the terminal-bus NIC, select the correct terminal-bus network adapter in SIMATIC Shell on the Engineering Station and confirm that the terminal-bus addresses resolve to the intended stations. If terminal-bus multicast must cross routed subnets, configure an appropriate SIMATIC Shell multicast proxy on a reachable PC. The reported engineer resolved this installation with host-name entries and adapter priority, but that result is topology-specific.

Select the Terminal-Bus Adapter

Siemens' PCS 7 PC Configuration manual describes configuring the communication module used for the terminal bus. In SIMATIC Shell settings, select the adapter that has the Engineering Station's terminal-bus IP address, then initialize network communication when prompted. Make sure the selected NIC is the terminal bus, not the management network or plant bus.

Check Name Resolution and Subnet Boundaries

Ping success by IP does not prove that station names resolve to the intended terminal-bus addresses or that SIMATIC Shell multicast discovery crosses the network path. Confirm each station's terminal-bus IP and name mapping and test name resolution from the Engineering Station. The source's successful resolution used entries in the Windows hosts file and changed interface metrics so the terminal-bus adapter had higher priority; apply such changes only with network administration approval and the site's address plan.

Configure a Multicast Proxy When Needed

Siemens documents a multicast proxy for networks where routers do not forward multicast traffic between subnets. The proxy must be a specific PC reachable in the other network segment; it is not an arbitrary unused IP. Select the multicast proxy in SIMATIC Shell on the relevant stations according to the PCS 7 PC Configuration procedure. A proxy is relevant to routed multicast and should not be added as a generic fix for every multi-NIC station.

Troubleshoot Discovery

Record the terminal-bus IP, subnet mask, gateway, DNS/hosts mapping, and adapter metric for the ES and each station.
In SIMATIC Shell, select the NIC assigned to the terminal bus and initialize communication.
Check that station hostnames resolve to terminal-bus addresses from the ES.
Confirm multicast routing or configure the documented proxy where subnets are routed and multicast is not forwarded.
Repeat discovery in SIMATIC Shell and check whether the OS station can be selected in STEP 7/PCS 7 engineering.
Keep plant-bus, terminal-bus, and management traffic separated according to the approved network design.

Verification

With the intended terminal-bus adapter selected, verify that the OS and other stations appear in SIMATIC Shell and that PCS 7 engineering can locate the expected OS station through that network. Confirm that remote-support and plant-bus communications still use their intended interfaces.

Limitations and Operational Precautions

The forum's hosts and interface-metric solution is a reported result for one three-network topology; it does not prove a universal discovery procedure. Incorrect metrics or host mappings can redirect other communications. The source contains a duplicated phrase for terminal bus where one network may have meant plant bus, so confirm the actual topology.

Engineer FAQ

Select the terminal-bus NIC in SIMATIC Shell, verify terminal-bus name resolution, and use a multicast proxy only when routed subnets block multicast. The forum's hosts-file and adapter-priority fix is topology-specific.

Technical References

Siemens, PCS 7 – PC Configuration (V9.1), terminal-bus communication and SIMATIC Shell settings: https://support.industry.siemens.com/cs/attachments/109794377/ps7pck_b_en-US.pdf
Siemens, PCS 7 Virtualization, §6.3.5 “Communication over multiple subnets,” explaining terminal-bus multicast proxy configuration: https://support.industry.siemens.com/cs/attachments/109737277/Manual_PCS7V81SP1_Virtualization_en.pdf