Key Takeaway
The S7-1200 PLC typically has an Ethernet port for communication, and the IP address can either be manually assigned or automatically assigned via DHCP. Default factory settings often configure the PLC to request an IP via DHCP. You can set a static IP address in TIA Portal by opening the hardware configuration, selecting the Ethernet interface, and specifying IP details like IP address, subnet mask, and gateway. A typical static IP example could be 192.168.0.1. Proper IP configuration ensures smooth communication with HMIs, SCADA, PCs, and other PLCs. Remember to match network settings between the programming device and the PLC to avoid connection issues during downloading or monitoring.
Default IP Configuration of S7-1200
By default, the S7-1200 doesn’t come with a permanent IP address. It’s typically set to obtain an address dynamically using DHCP. If DHCP is not available, it may fall back to a default IP range like 192.168.0.1 or an APIPA address like 169.254.x.x.
This is why many new engineers get confused when they try to connect the PLC directly to a laptop. No communication happens because the IPs don’t match. So the first step is always checking if both your PLC and PC are on the same IP range.
In most industrial environments, a static IP is preferred for reliability. DHCP can work, but if the IP changes after a reboot, your entire system might fail to connect — and that’s a nightmare in production.
How to Set or Change the IP Address in TIA Portal
Changing or assigning a new IP address to the S7-1200 PLC in TIA Portal is quite straightforward:
Open your TIA Portal project.
Navigate to the PLC under “Devices & Networks.”
Click on the Ethernet port.
Under “Properties > Ethernet Addresses,” choose either:
Static (Manual): Enter your desired IP address (e.g., 192.168.1.10).
Dynamic (DHCP): Allow the network to assign it automatically.
Make sure your subnet mask and gateway match the rest of your network.
Once done, download the settings to your PLC. It’s that easy — but don’t forget to ping the address from your PC to confirm it’s live.
Pro Tip: If you ever mess up the IP settings, you can reset them using the Siemens “Primary Setup Tool” or through a factory reset using the reset button on the CPU.
Static vs Dynamic IP Assignment (DHCP)
So, which one should you choose? Static or Dynamic?
Static IP means the address never changes. This is the gold standard in industrial setups. It ensures reliable, predictable communication with HMIs, SCADA, and programming devices. You set it once, and it just works.
Dynamic IP (via DHCP) works well in office environments or flexible test setups. But it introduces uncertainty — especially after a power cycle. If the PLC’s IP changes, all your linked systems break unless they support dynamic DNS or service discovery.
For a plant floor or factory, always go static. Use DHCP only when absolutely necessary or in non-critical environments.
Troubleshooting Network Connectivity
Sometimes, things just don’t connect — and you’re left scratching your head.
Here are a few common issues and how to fix them:
IP Mismatch: Ensure your PC and PLC are in the same subnet. For example, if your PLC is 192.168.1.10, your PC should be something like 192.168.1.20.
Firewall Block: Disable any active firewall or antivirus that might block PLC traffic.
Cable or Switch Issues: Use a known good Ethernet cable and check the LED indicators.
Incorrect Subnet/Gateway: If your subnet is wrong, even correct IPs won’t communicate.
A useful trick: Open the command prompt and try ping 192.168.1.10. If there’s no response, you know there’s a layer blocking the connection.
Always approach network issues step by step. Don’t guess — diagnose.
Best Practices for IP Address Management in Industrial Networks
Managing IP addresses in a factory setting isn’t just about plugging in numbers. It’s about clarity, consistency, and control.
Use an IP Addressing Scheme: Allocate ranges for PLCs, HMIs, SCADA, and engineering workstations. Example:
PLCs: 192.168.1.10–50
HMIs: 192.168.1.51–70
Document Everything: Keep a spreadsheet or internal wiki with all assigned IPs.
Avoid Conflicts: Never use DHCP unless absolutely needed. IP conflicts can crash systems.
Label Devices: Physically label each device with its IP for easy identification.
Conclusion
In industrial automation, IP address configuration is not optional — it’s foundational. A properly configured S7-1200 PLC ensures smooth communication with HMIs, SCADA, and other controllers. It’s what allows machines to talk to each other.
From setting static IPs in TIA Portal to troubleshooting mismatches, every step matters. So next time you fire up your S7-1200, remember: the right IP isn’t just a number — it’s the start of a stable, scalable automation system.
Whether you’re on the shop floor or configuring remotely, mastery of IP setup gives you control. And in automation, control is everything.