LOGO! Soft Comfort — learn the logic on screen before you touch a single wire
LOGO! Soft Comfort is Siemens' free software for building logic with function blocks and testing it instantly in simulation — with virtual switches and lamps, not real wires. You can get it wrong, fix it, and try again before the program ever reaches the module.
How to work with the software
Install and open the workspace
Download LOGO! Soft Comfort from Siemens and open a blank FBD sheet — drag and connect function blocks there with your mouse.
Get to know the block library
Find logic, timer, and counter blocks in the side panel — build your logic from them like building blocks.
Test it in simulation
Turn on simulation mode and click the virtual switches — watch the virtual lamps light up on screen and fix mistakes right away.
Save and transfer to the module
Once the logic works in simulation, save the file and transfer the program to the real LOGO! module — that's the only point where hardware comes in.
Why start with simulation, not hardware
real wires in step one
The classic beginner mistake is heading straight for the panel. Do it right — try the whole logic on screen first, and only touch the module once the simulation runs without errors.
FBD workspace
You program with function blocks (FBD) — you see visually how the signal flows from input to output, instead of writing code.
A ready-made block library
Drag and connect logic gates, timers, counters, and other blocks with your mouse — nothing to invent from scratch.
Virtual switches and lamps
In simulation mode you click virtual switches just like real ones — the screen shows immediately whether the logic works.
Fix mistakes with zero risk
While the program only lives on screen, getting it wrong is safe and cheap — nothing burns out, nothing needs unplugging.
Save and carry it with you
Save the finished program as a file and transfer it to the LOGO! module — it stays with you even after installation.
What this guide covers
The path from a blank program to working logic on screen.
- What the Soft Comfort workspace looks like
- How to use the block library
- How to turn on simulation and test with virtual switches
- The most common beginner mistake, and how to avoid it
- How to save and transfer the program to the module
Frequently asked questions
Do I have to pay for LOGO! Soft Comfort?
No, it's free software from Siemens — you can download and use it without paying, even without a LOGO! module connected.
Does simulation replace testing with real hardware?
No, but it catches most logic mistakes on screen already — what's left to check on the module is what simulation can't show, like real sensor signals.
What's the most common beginner mistake?
Starting straight at the panel and wiring, without trying the logic in simulation first. It's better to try everything on screen first, and only touch hardware once the program already works.
Does Soft Comfort work for more complex logic too?
It suits individual tasks, like lighting, pumps, or gates. If you have many points and need to cover a whole home, KNX is the better choice.
How do you transfer the program to the LOGO! module?
Once the simulation runs without errors, you transfer the program to the real module, where it stays saved even without a computer.
Ready to move from screen to panel?
Once your logic works in simulation, check out LOGO! modules and accessories in the shop.