Key Takeaway
To reset an S7-1500 PLC to factory settings:
Set the mode selector on the CPU to STOP.
Open TIA Portal and connect to the CPU.
In the online menu, choose “Accessible devices,” locate your PLC, and select “Reset to factory settings” (sometimes called “Reset to delivery state”).
Alternatively, you can use the CPU’s onboard display (if available). Navigate to “Reset” via the LCD screen, confirm, and execute the reset.
Resetting erases all programs and configurations. After reset, the CPU will return to default settings (no IP address if DHCP is enabled).
Always backup your project before resetting. Use reset cautiously, especially in operational systems, to avoid accidental downtime.
Soft Reset vs Hardware Reset Options
Before jumping in, you need to understand the two main types of reset: Soft Reset and Hardware Reset.
A Soft Reset is done through the software — specifically the TIA Portal. This doesn’t wipe everything. It’s more like a gentle restart. You’ll use this when the PLC gets stuck or you just need to refresh without losing your program.
On the other hand, a Hardware Reset is more serious. This involves physical interaction — pressing buttons or using the memory card to perform a factory reset. This type wipes all configurations and user programs.
So, when do you use what?
Use Soft Reset for troubleshooting minor issues.
Use Hardware Reset when reprogramming the controller from scratch or preparing it for a new deployment.
Steps to Reset via TIA Portal
Let’s go step-by-step. Imagine I’m beside you, showing this on the screen:
Open TIA Portal and go to your project.
Connect to the S7-1500 via Ethernet.
In the Project Tree, right-click on your PLC.
Choose “Online & Diagnostics”.
Under Functions, you’ll see the option for “Reset to Factory Settings”.
Choose the reset type – with or without retaining IP address.
Click “Execute”.
The system might ask for confirmation. Say yes only if you’re sure.
What Happens to Program and Configuration
This part is crucial, especially if you’re mid-project or working on a live system.
When you reset the S7-1500, depending on the type of reset, the following may happen:
Your user program might be deleted.
All parameter settings, IP configurations, and module settings may revert to default.
If a memory card is inserted, it may restore an old project automatically.
So it’s not just about pressing a button. It’s about knowing what you’re losing.
Think of it like formatting a hard drive — if your data isn’t backed up, it’s gone for good. That’s why many engineers panic post-reset. Don’t be that person. Plan ahead.
Backup Recommendations Before Resetting
Here’s the golden rule in automation:
“If it’s not backed up, it doesn’t exist.”
Always create a backup using TIA Portal:
Right-click the PLC in your project.
Choose “Upload to PG” (this copies the current state from the PLC to your PC).
Save the project with a clear name and timestamp.
Also, export important configuration files and parameter blocks. Store them on a secure network drive.
Troubleshooting Reset Failures
Sometimes, even a reset doesn’t go as planned. Here’s what to watch for:
PLC not responding to TIA Portal: Check the IP configuration. If you’re using DHCP, it might’ve changed.
Error LED blinking: Indicates something went wrong — maybe a missing or corrupted program.
Memory card conflict: If the card has an incompatible project, the PLC might boot loop or reject startup.
Reset doesn’t complete: Try powering off, remove the memory card, then try a hardware reset.
Always refer to the Siemens manual for error codes — they’re incredibly helpful.
Don’t hesitate to ask senior engineers. Everyone messes up resets at least once. The trick is learning from it without panicking.
Conclusion
Resetting a Siemens S7-1500 PLC might seem intimidating at first, but once you understand the process, it’s just another powerful tool in your engineering toolkit.
The key is preparation: know the difference between a soft and hard reset, use the TIA Portal wisely, and never reset without a proper backup.
In industrial environments, every second counts — and a misstep can mean hours of delay. So take it seriously, reset responsibly, and most importantly, always learn from the process.