If you've ever tried to spec a Siemens S7-1200 for a small project and been told it's 'too expensive' or 'overkill,' I hear you. I've been on both sides of that conversation. But as someone who's been reviewing technical deliverables for over four years, I'm going to tell you a different story.
Siemens PLCs are not just for big factories and big budgets. They are, in fact, the best bet for small-scale automation if you know what you're doing. And 'knowing what you're doing' means investing in the right training, wiring diagrams, and local support. That's the key. Not buying bigger hardware.
Look, I get it. When you're a small integrator, a maintenance tech at a small plant, or a solo entrepreneur building a machine, your budget is tight. You look at a Siemens S7-1500, and the price tag makes you flinch. So you grab an Allen-Bradley MicroLogix, or a Mitsubishi FX, or even a cheap clone. But I've seen the hidden costs of that decision—the ones that don't show up on the invoice. And let me tell you, they add up.
In Q1 2024, during one of our quality audits, we reviewed a batch of 25 small control panels built by three different vendors. Two used Allen-Bradley CompactLogix, one used a Siemens S7-1200 setup. Guess which one had the fewest wiring errors and the best-documented commissioning process? The Siemens one. By a mile. The engineer had downloaded the official Siemens S7-1200 wiring diagram from the support portal, followed it to the letter, and cited it in their test report. The other two? One had a short from miswiring the sensor commons, and the vendor couldn't even say what happened.
So here's my argument: the initial hardware cost is a trap. The real cost is in engineering hours, troubleshooting, and—most critically—downtime. A cheaper PLC might save you $200 on the BoM. But if it takes you an extra two days to program because the dev environment is clunky, or if you blow a module because the wiring diagram wasn't clear (or you skipped it), you've lost that money ten times over.
And I'm not talking theory. I once ran a side-by-side test with our engineering team. We gave them a $200 budget mock-up setup with a Siemens S7-1200 and a cheaper vendor's PLC, same basic function: controlling a small conveyor with two sensors. The task was to have it running in 30 minutes, using whatever resources they could pull online. Now, the Siemens team struggled at first—like, the first 5 minutes were 'Where's the manual?' But then they found the Siemens S7-1200 wiring diagram PDF (complete with pin numbers and recommended wire gauges), and the TIA Portal team found a step-by-step tutorial for a similar conveyor. They got it running in 22 minutes. The other team? 38 minutes, and they had to call a friend to ask about the power supply connections. That time is not free.
I know what you're thinking. 'Yeah, but that's if you have a trained engineer. We don't have time or budget for a Siemens PLC course.'
I used to think that too. I was the guy who would just 'figure it out' on the job. Looking back, I should have just taken the official Siemens training. At the time, it felt like a waste—a $850 course for something I could Google. But after wasting about 20 hours over two projects (or rather, closer to 30 when you count the rework from my 'creative' wiring), I finally took the official TIA Portal fundamentals course. It was 3 days. I learned things that saved me easily 100 hours over the next year. The diagnostic tools alone were a game-changer. Don't quote me on the exact hours, but I'd say it was a 10x return on investment, easy. And I know that's not just me. A friend at a small system integrator told me they mandate the S7-1200 course for all new hires, even junior techs. He said their defect rate dropped 40% in the first quarter after.
Now, I will say this—finding a good Siemens PLC course that fits a small budget is a pain. But there are good options. The official Siemens free eLearning modules on the S7-1200 basics are solid. And many local distributors now offer 1-day workshops specifically for small businesses. The price is often under $200. That's less than the cost of a blown relay module.
Another thing people miss is the local support and repair network. If you're a small shop and your PLC goes down at 2 AM on a Saturday, you can't afford to wait for a replacement to ship from overseas. You need someone who has an S7-1200 on the shelf. Siemens has one of the best local support ecosystems, at least in my experience. Over 4 years and reviewing 200+ items annually, I've seen that a third-party vendor with a Siemens line card usually stocks the common models. I've never had the same luck with some other brands.
I remember a case where a client's production line stopped because their cheap PLC's power supply failed. It was a $50 part. The vendor said '2-3 weeks for a replacement.' The client lost about $18,000 in downtime over 3 days before they could get a stopgap from another supplier. If it had been an S7-1200, I could have walked to a local distributor and had a replacement that afternoon. Or a used one from eBay. The community is huge.
So, I'm not saying Siemens is perfect for every small project. I'll be the first to admit the initial learning curve with TIA Portal can be frustrating. The first time I opened it, I had to close it and try again the next day, seriously. It's not as intuitive as some other entry-level software. And the safety documentation (the IEC 62443 stuff) can feel overwhelming if you just want to blink a light.
But here's the thing—once you climb that initial hill, the ecosystem is more powerful and consistent than anything else I've used. You learn one approach—like configuring a function block—and you can reuse it across the entire S7 family, from the Logo! up to the S7-1500. That consistency is a huge time-saver when you scale up. I've seen small integrators who started with the S7-1200 smoothly move to the 1500 for larger projects, using the same skills, the same TIA Portal projects (with minor tweaks), and the same wiring principles.
I know I sound like a Siemens fanboy—and maybe I am, a little. But it's earned. I've been burned by trying to save money on hardware and it costing me double in labor. I've seen small companies treated poorly by vendors who 'don't want small orders.' But I've also seen a small startup get incredible support from a local Siemens partner because they invested in the right training and used the right documentation.
So here's my advice: If you're doing a small automation job, resist the urge to buy the cheapest PLC you can find. Instead, invest in the S7-1200 or even a Logo! for the simplest stuff. More importantly, invest in the knowledge. Watch a free tutorial, look up the official wiring diagram, and if you can, take a short course. You'll build something more reliable, you'll sleep better at night, and you'll be ready for the bigger projects that will come.
Trust me on this one. I've reviewed enough failed panels to know.