Hello everyone,


I am an electrical/automation student, and I am currently learning PLC programming and HMI design. I have some experience with small school projects, such as controlling motors, sensors, basic automation sequences, alarms, and simple HMI screens.


However, I realize that school projects are quite different from real industrial systems. I want to improve my practical thinking and understand how PLC programs are designed in real factories.


So I would like to ask the engineers here:


Could you share some real industrial PLC/HMI problems or project scenarios that you have worked on?


For example:

• Machine control sequences
• Conveyor systems
• Pump or motor control systems
• Alarm handling
• Interlocks and safety logic
• Auto/manual operation
• HMI screen structure
• Troubleshooting cases
• Communication between PLC, HMI, VFD, sensors, or other devices

I am not asking for confidential company programs or private documents. I just want to learn from realistic examples and practice solving problems like an automation engineer.


Any advice, sample requirements, or real-world scenarios would be very helpful for me.


Thank you very much.

 

Here's a practical problem for you! Nothing too crazy, but it's a PLC program you will likely write a million times lol

Application: "Lift Station Monitoring and Control"

A lift station has two pumps, a radar level sensor, and two backup floats.

When the level in the wet well reaches 8 feet, a pump needs to turn on to drain the well to 4 feet.

Each time a pump is called to run, they alternate which comes on. The first time, Pump A is called. The second time, Pump B is called....

However, neither pump is allowed to run for more than 2 hours at a time, and if the level of the wet well exceeds 9 feet, both pumps must run to avoid flooding.

Lastly, if the radar level transmitter goes out or stops working, this control scheme MUST still operate as normal.

....

Write a PLC program for this application. Typically called "Lead Lag", "Pump Alternation", or "Duplex Pump Control".


EXTRA CREDIT:

Add a third pump (triplex pump control)