I Asked AI to Write My Ladder Logic. Here's What Happened.

"Write me a conveyor belt interlock with two sensors and an e-stop."

I typed that into an AI-powered PLC IDE last Tuesday at 3 AM. I was four hours into debugging a simple start/stop sequence that should've taken 20 minutes. My coffee was cold. My eyes burned. And I was starting to question my career choices.

Three seconds later, the AI generated this:

|----[ Sensor1 ]----[ Sensor2 ]----[ NOT EStop ]----( ConveyorRun )----||
|
|----[ ConveyorRun ]----[ NOT FaultCondition ]------------------( Motor )----||
|
|----[ EStop ]-----------------------------------------------( FaultLatch )----||

Perfect. Working. First try.

I stared at the screen for a full minute. Then I did something I haven't done in 12 years as a controls engineer: I went to bed before sunrise.

The Problem Nobody Talks About

Here's the truth about PLC programming that no one admits in LinkedIn posts or conference talks:

80% of our time is spent on repetitive boilerplate code.

Start/stop sequences. Safety interlocks. Alarm handlers. Timer cascades. We've written the same logic a thousand times, just with different tag names. Copy-paste from old projects. Tweak variable names. Pray you didn't miss a reference.

I once spent an entire afternoon debugging why a motor wouldn't start. The issue? I typed MotorRun in one rung and Motor_Run in another. One underscore. Three hours gone.

And we accept this. We call it "experience." We tell ourselves it's what the job is.

But what if it didn't have to be?

What Happened When I Let AI Write My Code

I'm not going to lie — I was skeptical. AI writing PLC code? Ladder logic isn't English. It's logic gates, timers, edge detection. It requires understanding hardware, safety, IEC standards.

But I was desperate. So I tried it.

Test 1: A Simple Motor Starter

Me: "Create a motor starter with start button, stop button, and overload protection."

AI: Generated a three-rung ladder diagram with seal-in logic, overload NC contact, and proper motor output. Included comments explaining each element.

Time saved: 15 minutes.

Test 2: A PID Temperature Controller

Me: "PID loop for oven temperature control, setpoint 250°C, input from thermocouple, output to SSR."

AI: Generated a Function Block Diagram with TON block for warm-up delay, PID block with tuned parameters (Kp=2.0, Ki=0.5, Kd=0.1), scaling blocks for 4-20mA signals, and alarm logic for over-temp.

Time saved: 45 minutes. Maybe two hours if I had to look up PID tuning formulas again.

Test 3: A Sequential Function Chart for Batch Process

Me: "SFC for mixing tank: Fill → Heat → Mix → Drain. Transition conditions based on level and temperature."

AI: Generated a complete SFC with 5 steps, 4 transitions, action qualifiers (N, L, D), and all the transition conditions I described. Even added a manual reset step I forgot to mention.

Time saved: An entire morning.

The Part That Actually Surprised Me

It wasn't just that the AI wrote code. It wrote good code.

The ladder rungs were organized. The tag names followed conventions. Safety interlocks were in the right places. Comments explained the logic in plain English.

But here's what really got me:

It worked in simulation. First try. Every time.

I tested all three programs in the built-in simulator. Watched the tags go true/false. Watched timers count. Watched the SFC step through its sequence. No compilation errors. No tag mismatches. No "undefined variable" nonsense.

Then I exported it to Rockwell L5X format and imported into Studio 5000. Still worked. Same program. Zero edits.

What This Actually Means for Us

I know what you're thinking. "Great, AI can write boilerplate. So what? Real controls work is more than start/stop logic."

You're right. But think about this:

• How many hours have you spent writing the same motor starter pattern?
• How many times have you copy-pasted an alarm handler and changed variable names?
• How many late nights debugging a typo in a tag name?
• How many projects where 70% of the code was boilerplate you'd written before?

What if all that just... disappeared?

What if you spent your time on the actual hard problems — system architecture, optimization, edge cases — instead of typing out the same interlock logic for the 500th time?

The Future is Already Here

I'm writing this because I wish someone had told me sooner.

AI isn't going to replace controls engineers. But controls engineers who use AI will replace those who don't.

The junior engineer who can generate a PID loop in 30 seconds is going to outpace the senior who still types every rung by hand. The contractor who can prototype three system architectures in an afternoon will win bids over the one still using Excel to plan logic.

This isn't theoretical. It's happening now.

What I'm Using Now

The tool I used is called Plaxio. It's a desktop IDE with AI built-in. You describe what you want in plain English, and it generates Ladder Diagram, FBD, or SFC code.

But here's what sold me:

• Vendor-neutral: Export to Rockwell, Siemens, Schneider, PLCopen. One codebase, any PLC.
• Built-in simulator: Test your logic before you touch hardware. See tags update in real time.
• Version control: Git integration. Branching. Diffing. Like software dev, but for PLCs.
• Auto-documentation: The AI generates project docs from your code. No more outdated Word files.
• It's free. No license fees. No vendor lock-in.

I'm not sponsored. I'm just an engineer who's tired of wasting time on problems we solved 20 years ago.

Try It Yourself

Download Plaxio. Give it one week. Try the AI on something simple — a motor starter, a timer cascade, whatever you're working on.

If it doesn't save you time, delete it. But I think you'll be surprised.

I was.