I Replaced a 24/7 Alarm Watcher with 30 Lines of Python and a Telegram Bot

Sebastian — Sat, 25 Jul 2026 06:19:49 +0000

Before this, I had never built a notification system. I just had a PC, a free Telegram bot, and a simple problem: alarms were firing on the plant floor, and by the time someone noticed on a dashboard, the downtime clock had already been running for minutes.

So I asked myself a dumb question: what if the alarm just... texted someone?

Turns out, it's a lot easier than it sounds.

Let me set the scene
Industrial alarms are usually built to be seen, not heard. A light turns red on an HMI. A tag flips in a SCADA system. If nobody's staring at that screen at that exact moment, the alarm just sits there, quietly costing minutes.

Meanwhile, everyone on a maintenance team already has a phone in their pocket.

So instead of building (or paying for) a bigger dashboard, I built something dumber and faster: a Python script that watches tag states and pings a Telegram group the second something goes wrong — and logs everything so there's a report waiting at the end of the shift, no manual tally required.

No database server. No new dashboard software. No licenses.

How it's wired together

[ PLC / data source ]
        |
        | tag values
        |
[ Python script — polling loop ]
        |
        ├── detects state change (off → on, on → off)
        |
        ├── sends message ──► [ Telegram group ]
        |
        └── logs event ──► [ alarms_YYYY-MM-DD.json ]
                                  |
                                  └── end of shift ──► [ Shift report: top 5 + downtime ]

Step 1 — Get the bot talking
Telegram bots are free and take two minutes to set up via @botfather. Once you have a token, sending a message is one HTTP call:

That's the entire notification layer. One function, reused for every alert.

Step 2 — Don't alert on values, alert on changes
My first instinct was to just check "is this tag true?" every second and fire a message. Bad idea — that spams the same alarm every second while it's active.

The fix: track the previous state, and only fire when it changes.

Output (in the Telegram chat):

🔴 ALARM: Tank1_Level triggered
🟢 CLEARED: Tank1_Level back to normal
Two lines of chat, zero minutes of someone staring at a screen to catch it.

Step 3 — Log everything, automatically
Every trigger and clear event gets appended to a JSON file for the day. No database setup, no schema — just a growing list of events with timestamps.

Step 4 — The part that actually saves time: the shift report
This is where it clicked for me. By shift end, that JSON file already has everything needed to answer the question every supervisor asks: "what actually happened today?"

Output:

No spreadsheet. No handover notes scribbled on paper. Just python report.py at the end of the shift.

Why this actually matters
This isn't a groundbreaking piece of engineering — that's the point. The value isn't in complexity, it's in closing three gaps that most plants quietly live with:

Detection lag: alarms sitting unnoticed on a dashboard
Notification friction: nobody wants another app, but everybody already has Telegram/WhatsApp on their phone
Reporting overhead: someone manually reconstructing "what broke today" from memory at shift change

Three Python functions, one free API, and a JSON file closed all three.

Where to go from here
If you want to build something similar:

Start read-only. Just alert and log — don't touch write commands until you fully trust the polling logic.
Batch alerts if things get noisy. If ten tags fire in the same second, group them into one message instead of flooding the chat.
Outgrowing JSON? Swap the file for SQLite — same logic, just a different storage layer.
Add more context to alerts. A tag name is fine, but a tag name + last known good value + how long it's been active is a lot more useful at 3 AM.

You don't need a SCADA overhaul to get real-time visibility. Sometimes it's just a bot, a loop, and a JSON file.

Built something similar with Slack, WhatsApp, or email instead of Telegram? I'd love to compare notes — drop a comment below.

Reading PLC Tags with Python: pylogix + Rockwell Automation 🐍⚙️

Sebastian — Fri, 24 Jul 2026 04:29:36 +0000

PLCs and Python don't usually hang out together. One's rigid, real-time, industrial. The other's flexible and everywhere. But put them together and things get interesting.

Enter pylogix — a Python library that talks directly to Rockwell/Allen-Bradley PLCs over EtherNet/IP. No OPC server, no extra middleware. Just Python. 🙌

Install it:

bash

pip install pylogix

Read a tag:

python

from pylogix import PLC

with PLC("192.168.1.10") as comm:
    r = comm.Read("Motor1_Running")
    print(r.TagName, r.Value, r.Status)

That's it. Three lines and you're pulling live data off a PLC. 🔥

Reading a few tags at once? Just pass a list:

python

tags = ["Motor1_Running", "Motor1_Fault", "Tank1_Level"]
with PLC("192.168.1.10") as comm:
    for r in comm.Read(tags):
        print(r.TagName, r.Value)

Writing? Possible, but be careful ⚠️ — only write tags you fully understand, never touch safety logic.

Why bother? Because once you can read tag data in Python, you unlock stuff PLCs just aren't built for:

🔔 Real-time alerts (email, Slack, even voice)
📊 Dashboards
🗄️ Logging to a database for trends
☁️ Cloud integration
A couple of real-talk tips:

Don't poll every millisecond — 1 tag read/sec is usually plenty
Handle disconnects, networks drop
Never expose your PLC to the internet 🚫
Python doesn't replace the PLC. It just gives it a voice. 🗣️

Have you connected Python to a PLC before?
What'd you use — Modbus, OPC UA, pycomm3? Drop it below 👇

python #plc #iot #automation #rockwellautomation #industry40 #manufacturing #tech

DEV Community: Sebastian

I Replaced a 24/7 Alarm Watcher with 30 Lines of Python and a Telegram Bot

**Reading PLC Tags with Python: pylogix + Rockwell Automation 🐍⚙️**

python #plc #iot #automation #rockwellautomation #industry40 #manufacturing #tech

Reading PLC Tags with Python: pylogix + Rockwell Automation 🐍⚙️