Siemens Logo! (Steuerung) Review: The Tiny PLC That’s Quietly Running Half the World

You know that moment when a simple control task somehow mutates into a monster? A handful of relays becomes a full DIN-rail jungle. Timer relays stacked on each other, wires criss-crossing like spaghetti, and every small change means rewiring half the cabinet. One fault, and you're hunting for a loose connection at 2 a.m. with a flashlight and a headache.

For hobbyists, maintenance teams, and small OEMs alike, "just a little control" has a bad habit of turning into a fragile, unscalable mess.

That's exactly the problem Siemens Logo! (Steuerung) is built to solve: taking those small, repetitive, relay-based tasks and turning them into clean, programmable logic you can change in software instead of with side cutters.

The Solution: What Is Siemens Logo! (Steuerung)?

Siemens Logo! (Steuerung) — often simply called "Siemens LOGO! logic module" in English — is Siemens' ultra-compact PLC-style logic controller for small automation tasks. It sits between dumb relays and full-blown industrial PLCs: smarter than a relay panel, smaller and cheaper than a full S7 system.

According to the official Siemens product page for LOGO!, the current generation (LOGO! 8 series) offers:

• Integrated digital and (on some types) analog inputs and outputs
• Built-in display and keypad on many models
• Ethernet interface as standard on LOGO! 8 modules
• Optional communication modules for expansion and remote access
• Free engineering software LOGO! Soft Comfort with drag-and-drop function blocks

In plain language: it's a small, rugged brick that replaces your relays, timers, counters, and a surprising amount of custom logic with one device you program from your laptop.

Why this specific model?

You might be wondering: with so many PLCs out there — from Siemens' own SIMATIC S7 to competitors like Allen-Bradley MicroLogix or Schneider Zelio — why do so many electricians, facility engineers, and even DIY makers rave about Siemens Logo!?

After going through Siemens' documentation and user discussions on forums and Reddit, a few themes keep coming up.

• It's built for "small but serious" jobs. LOGO! is ideal when a full PLC would be overkill, but you still need reliability. Think pump control, gate and door automation, lighting logic, compressor control, level monitoring, greenhouse ventilation, small machine logic, and more.
• It's beginner-friendly without being a toy. Users on Reddit and automation forums often call LOGO! a perfect first step into PLCs. The LOGO! Soft Comfort software uses function blocks (timers, AND/OR gates, counters, comparators, etc.) that you literally drag, drop, and wire virtually. But it's still Siemens-grade hardware that's used in real industrial panels.
• Ethernet and expansion make it "grow" with you. LOGO! 8 base modules include Ethernet, and Siemens offers expansion modules for extra I/O, communication, and specific voltages. That means you can start with one small panel door project, then later connect it to an HMI, another LOGO!, or an upper-level system.
• It's compact, standardized, and clean. Instead of a cluster of separate timers, counters, and relays, LOGO! consolidates them into one DIN-rail-width device. Panel builders in particular love how much space and wiring time it saves.

From a market perspective, Siemens LOGO! sits in the sweet spot: smarter and more flexible than dedicated relay logic, less intimidating (and often cheaper) than a full industrial PLC platform.

At a Glance: The Facts

Here's what the Siemens Logo! (Steuerung) brings to your panel in practical terms, based on Siemens' official LOGO! 8 product information.

Feature	User Benefit
Compact logic module with integrated I/O	Replaces multiple relays, timers, and counters with one device, cleaning up your control cabinet and simplifying troubleshooting.
LOGO! Soft Comfort engineering software (function block programming)	Lets you design, simulate, and modify your logic visually on a PC, so changes are made in minutes, not hours of rewiring.
Ethernet interface on LOGO! 8 base modules	Enables networking with other LOGO! units, HMIs, or higher-level systems for remote monitoring and data exchange.
Modular expansion with additional I/O and communication modules	Allows you to start small and expand later as your application grows, without redesigning from scratch.
Integrated display and keypad (on many models)	Provides on-site status, parameter adjustment, and manual operation without an external HMI.
Predefined function blocks (timers, counters, PID variants, logic gates, etc.)	Simplifies complex control tasks into reusable blocks, lowering the barrier for users who are new to PLC programming.
Designed for industrial environments	Delivers higher reliability than hobby microcontrollers in electrical cabinets, making it suitable for commercial and light industrial use.

What Users Are Saying

Siemens LOGO! doesn't have the hype of a consumer gadget, but dig into automation subreddits and electrical forums and you'll notice a consistent tone: respect.

Positives that come up frequently:

• Easy learning curve: Many users say they started with LOGO! as their first PLC and felt comfortable after a weekend of experimenting with the software.
• Reliable hardware: In discussions, electricians and facility technicians report LOGO! units running for years in panels with minimal issues.
• Perfect for "one-off" solutions: People mention using it to automate gates, lighting, small pumps, and retrofits where a full PLC would be too much.
• Free or accessible software: LOGO! Soft Comfort is commonly praised for being approachable, especially compared to some heavier industrial IDEs.

The main criticisms and trade-offs:

• Not a full-scale PLC: Advanced users on Reddit are quick to point out that for large, complex machines or high-speed processes, you'll hit LOGO!'s limits and should move to SIMATIC S7 or similar.
• Limited I/O on the base unit: Out of the box, it's intentionally small. For bigger jobs, you'll need to add expansion modules, which increases cost.
• Vendor ecosystem: As with most Siemens products, you're in the Siemens ecosystem — which many see as a positive, but it's a consideration if you're mixing lots of brands.

The overall sentiment, though, is clear: as a smart relay / micro-PLC for small automation tasks, Siemens Logo! earns strong trust from people who have to live with their control panels every day.

It also helps that Siemens AG, the global industrial giant behind LOGO!, is a publicly listed company (ISIN: DE0007236101), which reassures buyers looking for long-term availability and support.

Alternatives vs. Siemens Logo! (Steuerung)

The logic module and micro-PLC market is crowded, so how does Siemens Logo! compare to the usual suspects?

• Versus Schneider Zelio / Eaton Easy / similar smart relays:
  These are LOGO!'s closest rivals. Feature sets are broadly comparable for basic relay replacement. Where LOGO! often pulls ahead is in its ecosystem: LOGO! 8 with Ethernet and Siemens' broader automation world (HMIs, drives, higher-level PLCs) gives you a more scalable path if your project grows.
• Versus full PLCs (Siemens SIMATIC S7, Allen-Bradley CompactLogix, etc.):
  Full PLCs are more powerful and better for large machines, safety systems, or high I/O counts. They're also more expensive, more complex, and overkill for a garage door, a water tank, or a simple conveyor. LOGO! wins when you want "just enough brain" without the overhead.
• Versus hobby microcontrollers (Arduino, Raspberry Pi, ESP32):
  Makers love microcontrollers for flexibility and price, but they aren't designed as drop-in industrial components. LOGO! is built for switchboards: DIN-rail mounting, industrial power supplies, defined operating ranges, and a programming environment aimed at electricians, not software developers. If the application is mission-critical in a commercial or industrial setting, LOGO! is the safer, more professional choice.

In short: if you need massive flexibility and you're coding in C or Python, microcontrollers win. If you're building a full factory line, use a PLC. But for that huge in-between space — the pumps, gates, lights, fans, and small machines that quietly keep everything running — Siemens Logo! stays particularly compelling.

Final Verdict

Siemens Logo! (Steuerung) is one of those products you rarely notice until you start looking for it. Then you see it everywhere: in pump stations, in small OEM machines, in building automation panels, even in serious DIY projects that need to "just work" for years.

If you're fighting with:

• Messy relay logic you're afraid to touch
• Patchwork timers and contactors that are a nightmare to modify
• Projects that are too important for a hobby microcontroller, but too small for a full PLC

then LOGO! is almost tailor-made for you.

Its biggest strength isn't any single spec line — it's the way everything comes together: compact hardware, industrial reliability, intuitive block-based programming, Ethernet connectivity, and a clean upgrade path deeper into the Siemens automation ecosystem when you need it.

Is it the most powerful controller on the market? No. It's not supposed to be. Siemens Logo! is the quiet, compact problem-solver that turns chaos into order in small automation jobs. And if you're the one who has to answer the call when something fails at midnight, that reliability and clarity might be the most important feature of all.

For anyone from hands-on electricians to plant maintenance to serious makers who want to step into professional automation, Siemens Logo! (Steuerung) is absolutely worth a place at the top of your shortlist.