How to Wire a PLC

Frequently, people ask, “How do I wire a PLC?” The answer is simple: follow the wiring diagram! But how do you create that diagram? By referring to the sample manual, of course! Where can you find these manuals? Just like when you buy a phone, it comes with a user manual!

PLC manufacturers provide various manuals to help users understand how to use their products. Therefore, all wiring diagrams and instruction usage for PLCs are derived from these manuals. If you read the manuals carefully, you can solve any problem. Take wiring, for example; any PLC manual provides clear instructions on how to wire the device. For instance, Siemens’ S7-200 Smart series.

As shown in the image above, this is the wiring instruction for the SR20 model. It clearly indicates how to wire the inputs, outputs, and power supply. You only need to draw the circuit diagram according to the manual’s instructions. Of course, if you find it too cumbersome and are just learning, you can skip drawing the circuit diagram and wire it directly.

So, as long as you read the manual carefully, you can solve any problem. The biggest misconception among beginners is that they don’t like to read manuals. Instead, they seek answers everywhere, often saying, “I’m waiting online, it’s urgent!” With such an attitude, how can they learn? Some people prefer to buy various books, but many of these books are designed to deceive beginners, merely copying and pasting from the manuals. Of course, there are also well-written books, but it’s challenging for beginners to distinguish them.

Therefore, for those starting from scratch with PLCs, reading the manual carefully is the best method!