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PCB to Schematic Diagram
PCB to Schematic Diagram
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Here are step by step introductions on how to convert PCB to schematic diagram and schematic diagram to PCB file.
Step 1: The engineer analyzes the PCB layout through the circuit board and then divides the circuit into several units.
Step 2: Prepare two computers, one of which is used to view PCB documents, and the other is used to draw circuit diagrams.
Step 3: Retrieve the components in the unit circuit and do layout according to our work experience.
Step 4: Highlight the PCB document on the computer and then link it to another computer. After the link is completed, the network needs to be deleted.
Step 5: Repeat the first two steps until all files in the PCB document are deleted. After that, the engineer can optimize the schematic.
How to draw circuit diagrams according to real products?
When repairing electronic products, engineers often encounter problems finding the drawings, especially for legacy products; the circuit diagrams may no longer exist. In this case, to analyze and improve the product, it is necessary to draw a circuit diagram based on the actual product. The skills of this operation are as follows:
1.Use the components with a large volume and many pins as a reference for drawing. Use this as a reference to start drawing, which can ensure accuracy andimprove work efficiency.
2. When an engineer is printing a circuit board, be sure to label the components and pay attention to the regularity of the serial number. They cannot randomize or remember which one to write. Write and arrange according to a particularorder and rules to ensure that it is not easy to make mistakes in the drawing process.
3. Without marking the serial number of the components, if the engineer wants to improve analysis and proofreading, you have to number the components yourself. It is not annoying;otherwise, the later work will be more difficult. Important components must be marked so that they will not be missed in the process of drawing the schematic.
4. Correctly distinguish the various wires on the circuit board. There are various wires on the circuit board,such as power wire, ground wire, signal wire, These wires have different layout positions, rules, and functions. When drawing a schematic, you must figure it out.
5. When drawing a sketch, be sure to use transparent tracing paper and mark it with colorful pens. It is convenient to identify, modify,and analyze the circuit to reduce errors. In addition, when drawing a circuit diagram, try to find a similar circuit diagram for reference so that there is a multiplier effect, which is very worthy of reference for newcomers.
It can be seen from the introduction that the process of converting a PCB to a schematic diagram is not difficult. Still, many novices lack experience or have not operated before, so they will find it challenging to convert PCB into schematics.
Protel+PCB Convert Into Schematic – Detailed Steps
Full raiders from Protel PCB to SCH
This article takes the 4 Port Serial Interface, provided by Protel 99Se, as an example. Open the PCB diagram, select the menu File-Export, export the Protel network table; the file name is abbreviated as Serial.Net. 2. Start the program Omninet for Windows, select Protel as the input file type (Type). In Input File 1, use Browse to specify the location of the netlist file. Select EDIF as the output file type (Type). In Output File 1, specify the file name and path of the output file. Then click Run (the running icon).
An output window pops up. Click Accept Data. Click “OK” when finished, and then click “Done” to close the output window. Exit Omninet for Windows.
3.Start the E-Studio software and open the EDIF file generated in step 2
Right-click the Serial.EDF file and select Generate Schematics:
The system pops up a window
Click OK.
5. Select menu File-Save As, and select ORCAD as the output format.Select Design v9.10 in the Save As drop-down menu.
Click Save to save. Click “OK” in the pop-up window to end.
The generated schematic can already be opened in ORCAD. The drawings are a bit big! The picture below is just its parts.
There is no hierarchy concept in drawings. No matter how complicated the circuit is, there is only one plane graph.
6. Convert ORCAD schematics into Protel schematics.
Because the output format of E-Studio does not have Protel, it must be converted separately. Protel 2004 is recommended for a better conversion effect.
Start DXP 2004, select menu File-Open, select Orcad Capture Design(*.DSN) for the file type.
Click “Open.” An error occurred during the opening process, but the file conversion was successful. Click OK to close the error window.
Double-click 1.SchDoc, the file can be opened normally. The picture below is part of the file:
Select the menu File-Save AS, select Schematic Binary 4.0 (*.Sch). This is the format that 99Se can open.
At this point, the conversion of Protel 99Se PCB to the schematic diagram is complete.
It should be noted that this conversion may be useful for those with fewer components on the PCB. If there are many components on the PCB, the converted schematic diagram will be very large, and the network connection is extremely complicated. At this point, it is still difficult to interpret due to the lack of hierarchy or main thread. It is also not to be divided into multiple sub-graphs, and all networks are all connected.
In addition, the unconnected pins in the PCB no longer exist on the converted schematic. As shown in the example below:
Another disadvantage is that the footprint information of the component is gone and must be filled in again.
Although there is no footprint information, the network name is kept intact. After network comparison, no missing network is found.
A Basic Guideline from Schematic to PCB Design for Altium Designer
The electronic engineering industry is so vast and rapidly growing that technology is evolving day by day. There are currently numerous open-source software or Electronic Design Automation (EDA) or CAD software available to help designers design their electronic circuits and lay the PCB design along with tools available in the software to generate files that will be used directly by PCB fabrication house.
Among these software, the most popular one is ALTIUM designer. The Altium Designer 18 will be discussed in this article. The Altium Designer gives you a complete platform where you can turn your imagination and ideas into reality.
We will discuss three main features of the Altium designer in the following sections: 1- Schematic Capture, 2- PCB layout, and 3- Fabrication Output Files.
Schematic Capture
The first step in turning the idea into reality is to do manual design or hand sketch on paper. This gives a clear understanding to the designer to know what he is looking for. Now the design on paper will be transferred to a CAD software like Altium. This process is called schematic capture. Having knowledge of the software, an expert will professionally capture the design in the schematic window.
File >> New >> Project >> PCB Project. Then right click on the project to “Add New to Project” >> Schematic
You can save your PCB project and schematic file with *.PrjPcb and *.sch extensions respectively. After saving, you can now start the placement of components from the library on the rightmost menu. You can add the manufacturer libraries available directly from the Altium website.
Just download the library zip folder. Unzip it and copy-paste the folders inside C:\Users\Public\Documents\Altium\AD18\Library\ this folder. Now find the component in the library and place them on the schematic one by one. Ctrl+R will rotate the component. Press and hold the right click to “Pan,” and the Left Ctrl + Right-click will zoom in and out.
The top menu shows the wire, GND, library, place port, place text, move, drag, and select options.
The left panel shows the project files like schematic Diagram, PCB, Gerber, BOM, and other files are shown as sub-folder files inside the main project. Any changes made in the schematic will mark with a red symbol on the left panel schematic file. After you save changes, the red mark will disappear.
Now you interconnect the components using the wire or bus option. GND, VCC, and other signal ports can be placed accordingly. This will correspondingly generate “NETs.” The NET is the interconnection between two leads/legs of components. The net name shows the details of its connection. You can go to tools >> preference >> Schematics >> General, where you can edit and change the properties of the existing schematic sheet, like snap and visible grids.
You can also annotate your components designators by Tools >> Annotation >> Annotate Schematics. You can change the sheet size by Right Panel Properties >>Page Options >> Formatting and Size >> Custom, and change the values of width and height according to needs, and change orientation to landscape or portrait. You can also switch between the units of measurement mm and mils.
The schematic capture is the basis of the PCB layout coming in the next step. Hence schematic capture should be completed free of errors. There should not be any error in the schematic design, and it must be cross-checked by another verification engineer to evaluate for any faults in the design. Otherwise, the wrong schematic will be translated into PCB and cause PCB not to function as expected.
PCB Layout
Now the next step is the PCB layout step. Right-click on Project panel >> Add new to Project >> PCB layout. A black color window will appear. This is the PCB layout documents where you will design the PCB layout. Now go to the schematic window and do the following:
Project >> Project options >> Class generation >> Uncheck generate rooms and uncheck electronic component classes. This is done to avoid any unwanted errors in PCB.
Now go to the schematic window. Design >> Update PCB Document. This will open the “Engineering Change Order” window. Now click on validate changes and then click execute changes. This will generate a green color tick sign on the right of the window. This shows everything is OK. Now go to the PCB document, and on the bottom right, your components will be available.
Drag and drop the components one by one onto the board. Now to reshape the board and go to View >> Board Planning Mode 1. You will see that the board color turns to green from black. Now go to Design >> Redefine Board Shape. Now the green color plus pointer will appear. You can now redefine the boundaries of your PCB board according to your needs. Remember to connect the last final edge with your starting edge/corner to complete the board shape. You can also use the edit board shape or modify board shape to change the board’s shape or style.
Now go to Design >> Rules. You can edit the PCB layout design constraints according to the PCB fabrication house capacity and limits and your design requirements. This is very important because while laying out PCB design (e.g., routing, placement of components, holes, vias, and other inner and outer layers), if there are violating constraints, the Altium will give you an error and will not proceed.
The main design rule constraints/clearances that need to be taken care of are track to track, track to SMD or THT pad, track to via, track to copper, SMD pad to SMD pad, SMD to THT pad, SMD pad to via, SMD pad to copper, THT pad to THT pad, THT pad to via, THT pad to copper, via to via, via to copper, and copper to copper clearances. Moreover, the maximum and minimum routing width and preferred values need to be defined. Solder masks and power planes with power pads constraints are also needed to be defined in design rules. Likewise, maximum and minimum via diameter and preferred values can be set in “Routing via Style.”
Now go to Design >> Layer Stackup Manager. This will show you the layer stack-up details, such as thickness, material, layer type, and name.
Now go to Route >> Auto Route >> All >> Route All. This will help you automatically route your components placed on the PCB according to the rules defined in the design rule wizard. The auto-routing will save ample time and effort but may not be a good choice when special care is needed for special ICs for EMI and other thermal considerations.
After everything is complete, go to Tools >> Design Rule Check (DRC). Running the DRC is important as it will identify any violations of design rules.
Fabrication Output Files:
Now that your PCB layout is done, it is time for Gerber and NC Drill File generation. These files are called PCB fabrication output files. Go to Files >> Fabrication Output >> Gerber Files. And NC Dill File. Select the appropriate unit and format for your Gerber and check to mark the “plot” of the corresponding layer you want to create Gerber. Keep all other parameters the same, and click OK.
For NC (Numeric Controlled) Drill File, checkmark the “Generate Separate NC Drill Files for plated and non-plated through holes” and keep all other parameters the same and then click OK.
Convert Eagle Circuit Diagram to Altium Designer PCB Format
Now that open source hardware is prevalent, many open-source hardware manufacturers will make circuit diagrams public. For example, for Arduino, we can download the Arduino Eagle file on the official website. Still, many people don’t know the Eagle drawing software very well. So you need to convert the file into a format that can be opened with Altium Designer.
Download the ULP file to be used on the official website of Eagle circuit diagram drawing software.
Put the file in the ULP folder under the Eagle installation directory, as shown in the figure:
4. Click the ULP command in the command toolbar.
5.Select “export-protelpcb.ulp” in the directory of the pop-up dialog box and click to open.
6.Choose a suitable path and save the converted PCBfile.
7.After clicking save, the following dialog box will pop up in the Eagle software, click OK.
8.At this point, the conversion of the PCB diagram has been completed. Double-click the saved file to open the file with Altium Designer, as shown in the figure:
8 Ways to Restore PCB Schematic Diagram According to PCB Board
When encountering some small objects, or encountering electronic products without drawings, you need to draw the circuit schematic according to the real thing.
There are the following points:
1. Select electronic components such as integrated circuits, transformers, transistors, etc., which are bulky, have many pins and play a major role in the circuit, and then draw from the selected reference pins to reduce errors.
2. If the component number (such as VD870, R330, C466, etc.) is marked on the PCB, since these serial numbers have specific rules, the components with the same Arabic numerals after the English alphabet are the same functional unit, so the drawing should be used. Correctly distinguishing the components of the same functional unit is the basis of the drawing pcb layout.
3. If the serial number of the component is not marked on the printed board, it is best to number the component yourself for easy analysis and proofreading. When designing printed circuit board components, the manufacturer generally arranges the components of the same functional unit relatively in order to minimize the copper foil routing. Once you find a device that has a core function, you can find other components of the same functional unit as long as you can find it.
4. Correctly distinguish the ground, power and signal lines of the printed board. Taking the power supply circuit as an example, the negative terminal of the rectifier connected to the secondary of the power transformer is the positive pole of the power supply, and a large-capacity filter capacitor is generally connected between the ground and the ground, and the capacitor casing has a polarity mark.
The power and ground lines can also be found from the three-terminal regulator pins. When the factory is wiring the printed circuit board, in order to prevent self-excitation and anti-interference, the ground copper foil is generally set to the widest (high-frequency circuits often have large-area grounded copper foil), the power supply copper foil is second, and the signal copper is used.
The foil is the narrowest. In addition, in electronic products with both analog and digital circuits, the printed boards often separate their ground lines to form an independent grounding grid, which can also be used as a basis for identification and judgment.
5. In order to avoid excessive wiring of the components, the wiring of the circuit diagram is cross-interleaved, resulting in a messy picture, and the power supply and ground lines can be used in a large number of terminal markings and grounding symbols. If there are many components, the unit circuits can be drawn separately and then combined.
6. When drawing a sketch, it is recommended to use transparent tracing paper, and use a multi-color pen to draw the ground wire, power cable, signal wire, components, etc. by color. When modifying, gradually deepen the color to make the drawing visually eye-catching for analysis of the circuit.
7. Proficiency in the basic composition of some unit circuits and classic drawing methods, such as rectifier bridges, voltage regulator circuits and op amps, digital integrated circuits. These unit circuits are directly drawn to form a frame of the circuit diagram, which can improve the drawing efficiency.
8. When drawing a circuit diagram, you should find a circuit diagram of a similar product as much as possible for reference, which will do more with less.