Hey r/PLC,

Let’s be honest, we’ve all been there: you are elbow-deep in a machine, trying to debug a sensor, and you need to toggle a single bit... but the physical HMI is 20 meters away.

I’m a PLC engineer based in Hungary (18 years of experience in the automotive sector, currently at Bridgestone). After years of dealing with clunky workarounds, I decided to build my own tool as a passion project: a **native Android HMI app** that communicates directly with Mitsubishi controllers via SLMP (MC Protocol). No intermediate OPC server, no PC routing, no cloud subscription BS. Just your phone and the PLC.

**The coolest feature I added:** I wrote a "Smart Dual Connection" logic. You can set up a Local IP (factory Wi-Fi) and a Remote IP (WAN/VPN/DDNS). When you open the app, it automatically pings/checks the network environment (reading M0 or CPU type) and seamlessly routes the traffic to the correct IP. You don't have to manually switch profiles when you leave the plant.

**Where I think this app shines (Use Cases):**

* **Commissioning & Troubleshooting:** A pocket-sized mobile HMI for machine installations, fast I/O checks, and debugging without constantly running back to the main panel.
* **Rapid Prototyping:** Makes testing during PLC development a breeze with a UI you can quickly edit and tweak on the fly.
* **Physical HMI Replacement:** For average or simpler machines, this app can completely replace a costly physical screen.
* **Upcycling Old Devices:** Got a dusty Android phone or tablet in a drawer? As long as it runs Android 7.0+, you can mount it to a cabinet and give it a second life as a dedicated, low-cost HMI panel.
* **Home Automation:** Perfect for controlling your garage doors, lights, or sprinklers if you are running your smart home on a Mitsubishi controller.

**Why I need your help:** It runs perfectly on my home FX5UC test bench. However, I know from 18 years of pain that Mitsubishi SLMP implementations can be wildly different (e.g., the built-in Ethernet port on a QnUDVCPU behaves completely differently from a dedicated QJ71E71-100 module).

I’m currently running a **Closed Beta** on Google Play, and I need a few automation guys who have access to different hardware (Q-series, L-series, older FX, etc.) to try to break my connection logic and give me some raw engineering feedback.

**What’s in it for you?** Anyone who helps me out with testing and provides useful feedback (bug reports, UI ideas, hardware compatibility) will get to **keep the app permanently**.

*(I've attached a few screenshots so you can get a sneak peek of the UI and the dual connection setup.)*

If you have a Mitsubishi PLC around and want to take it for a spin, drop a comment below or send me a DM, and I’ll send you the beta invite link!

Cheers!

I got tired of walking to the physical panel, so I built a native Android HMI for Mitsubishi PLCs (Direct SLMP). Looking for Beta Testers!