SOLIDWORKS, Electrical Design

How to define a PLC in SOLIDWORKS Electrical

By Sawyer Gara on April 19, 2022

SOLIDWORKS Electrical is a great tool for designing electrical schematics in 2D and having it represented in our 3D SOLIDWORKS assemblies. We know that we can create 2D symbols of all different types of components including motors, resistors and terminal strips that also maintain associativity back to our component library. This library holds all sorts of information about the component including manufacturer, location and any other relevant data. A common question I receive from clients is: “I do a lot of electrical design using PLCs. Typically, I just draw boxes and type in any information I might need but this is very time consuming. Is this a better way?” Fortunately, SOLIDWORKS Electrical makes this process as seamless as adding in any other component.

Types of PLC

When talking about PLCs, we split them into two different categories: Simple (fixed) or Complex. Simple is what the name implies. We can grab these PLCs off the shelf and put it in our project. There is not a whole lot of customization with a simple PLC as they are non-expandable. On the other hand, a complex PLC gives us full control over the assembly and selection of the individual components. With a complex PLC, the designer can decide the number of inputs and outputs on the module. With SOLIDWORKS Electrical, we can easily pick and represent both types in our electrical project.

PLC Part Selection

Inside of SOLIDWORKS Electrical, we have a PLC Manager that makes defining the PLCs in our project a breeze. Inside the manager you can hit the “Add PLC” button and select between adding a PLC Mark and a Manufacturing Part. If all you wanted was a simple PLC, pick Manufacturer Part, and then select the part you want to add. All the relevant information is pulled from the library and inserted into the PLC Manager.

PLC Manager

Making complex PLCs is a little bit more hands on. After adding a PLC Mark, you can either assign a rack to the PLC or dive right in to adding in modules. When adding modules, you can mix and match manufacturers while adding things like power adapters, controllers and your input/outputs. If you want to reorganize the slots, you can do so using the arrows to move things around. Hitting select will add the newly organized PLC into your PLC Manager.


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PLC Input/Output Assignment

With your PLC created and the slots defined with the relevant modules assigned, you can start to specify the Inputs and Outputs for the PLC. There are a couple of different ways we can do this. The first way is to use our Input/Output Manager to predefine an Input or an Output. In the manager, you can specify different types of Inputs/Outputs and a description for it.


At this point, you can go back to your PLC Manager, right-click the module you want to assign, and then assign the existing Input/Output you just created. This will update the input/output to have an updated reference and address added to it.


The other way to assign an input or and output is to right-click on the module and add a new PLC Input/Output. This will create a new I/O in the Input/Output Manager that is already linked to the module. From here you’re able to change the description to better suit the application.

Dynamic Symbols

With the PLC fully defined and customized in our PLC Manager, it might make sense to insert it into our schematic to better represent our system. From our PLC Manager, you can select the slot you want to insert and then hit the “Insert PLC” button. This will generate a symbol for our schematic based on the PLC we created and once placed will have the relevant information we assigned in the PLC Manager.


Additionally, if you only place a fraction of the modules from the PLC, the tool will automatically generate the remaining modules as a new symbol to allow you to place it elsewhere in the schematic.

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Channel Address Propagation to Terminals

Typically, after going through the set up for our PLC and placing that PLC in our drawing along with the Channel Addresses, you might want to pass that information downstream through the wires to our terminal strips to make it easier to track. Once again, fortunately SOLIDWORKS Electrical has a solution for that. Within SOLIDWORKS Electrical, we can “Propagate Data to Connected Objects." What this means is we can take information from one part of our schematic and push it down to another part of a connected object.


Rather than manually following wires and making sure everything is correct without any typos, we can rely on rules set up in SOLIDWORKS Electrical to take care of the work for us. In this case, we can set up rules that take the Channel Addresses from the PLC we have inserted in the schematic, pass that to the wire mark and then down to our terminal strip. This is going to save time and effort while ensuring the information is propagated correctly.

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