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PLC panel photos tell you almost everything about the person who built or dismantled them. This week reviews five real ones from the community, plus the honest answer to what a beginner should actually learn first.
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Learn more at Joltek:
Control System Modernization Strategy: https://www.joltek.com/blog/control-system-modernization-strategy
Rockwell PLC Lifecycle Migration Guide: https://www.joltek.com/blog/rockwell-plc-lifecycle-migration-guide
Connecting an Allen-Bradley PLC to Ignition: https://www.joltek.com/blog/connecting-allen-bradley-plc-ignition
The best panel this week is a large enterprise Rockwell build: a ControlLogix rack with a second fixed chassis alongside it, digital and analog I/O broken out to the standard field terminals, a PanelView on the door that looks like a 7 Performance, and clean labeling throughout. Two notes on it. There is room in that enclosure to have scooted the chassis over and bought identical racks rather than mixing sizes. And there is no switch visible, which is unusual at that scale, though it works if the single controller runs one port to the remote rack over EtherNet/IP and the other to the plant network. No cooling either, which is defensible with no VFDs in the cabinet but is not what I would normally expect.
The worst panel is the one that makes the point. Someone acquired a cabinet holding ten Festo servo drives with a Weidmuller ProTop supply feeding 24 volts at 40 amps, and every motor and feedback cable has been cut off at the drive. Those terminal blocks release with a small screwdriver into the blue notch. It takes seconds. Instead the whole harness was severed, so whoever bought that equipment now has to strip and re-terminate every conductor before anything runs. It is recoverable and it was unnecessary, and it tells you what kind of shop handled the teardown. If you are buying used industrial hardware, look at how it came out of the building.
A first PLC project also came in: an AutomationDirect Productivity controller driving Finder relays for a low voltage house lighting retrofit, on a WAGO supply at 5 amps. It works. The main change would be a much shorter DIN rail, because everything on there fits in about a foot and the long runs to the relays make the wiring harder to read than it needs to be. If you want to push it further, Home Assistant running in Docker alongside the PLC gets you phone and browser control without touching the logic.
Then a piece of history. Someone picked up the portable Allen-Bradley PLC-5 demonstration trainers, the units people were trained on, and they power up and boot clean. The parallel port is still on the side. The genuine problem underneath the nostalgia is software: when an OEM discontinues hardware they usually pull the ability to buy the programming software with it, and plenty of plants still run PLC-5 and SLC families today. The people maintaining those lines need RSLogix 5 and cannot simply purchase it. Distributors can sometimes route you to a license, but it is harder than it should be.
The last question is the most useful one. Someone learning on a borrowed board with a CompactLogix L38ERM and a Micro850, using Connected Components Workbench and Studio 5000, asked what to focus on without disappearing down rabbit holes. Focus on Studio 5000, because it is the platform of choice across large enterprise while the Micro850 family has a much smaller install base. Learn ladder logic first, especially in North America. Then FactoryTalk View ME, which lets you build screens and simulate buttons and sensors against the controller from your laptop with no physical HMI. After that, Ignition, which is free to learn through Inductive University and runs on a laptop, and which pulls you naturally into Ethernet communication, MQTT and OPC UA. That progression is PLC, then HMI, then SCADA and data, and it is the order that actually builds on itself.
Timestamps
0:00 The S7-1500 display meme explained
2:20 A large enterprise ControlLogix panel reviewed
4:10 The PanelView, the missing switch, and no cooling
6:20 A gutted Festo servo drive cabinet
8:00 How those drive terminals should have come apart
9:40 Why cut cables tell you who did the teardown
10:50 A first PLC project: house lighting on a Productivity controller
13:20 DIN rail length, and Home Assistant as the next step
14:10 PLC-5 trainer units and the software problem underneath
18:10 What should a beginner actually learn first
19:20 Reading the board: CompactLogix L38ERM and Micro850
21:10 Studio 5000 over CCW, and why
21:50 Ladder logic, FactoryTalk View ME, then Ignition
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