The package of parts can be specified when designing the circuit diagram or when introducing the network list. When designing the circuit diagram, you can specify it in the Footprint setting item in the part properties dialog box, or you can specify the part package when importing the netlist.
Question 1: What is part packaging and what is the difference between it and parts?
Answer: (1) Part packaging refers to the appearance and solder joint position indicated when the actual part is soldered to the circuit board.
(2) Part packaging is only the appearance and solder joint position of parts, and pure part packaging is only the concept of space, so different parts can share the same part packaging; On the other hand, the same kind of parts can have different packages. For example, RES2 stands for resistance, and its package forms include AXAIL0.4, AXAIL0.3, and AXAIL0.6, etc. Therefore, when selecting welded parts, you should know not only the name of the parts but also the package of the parts.
(3) The packaging of parts can be specified when designing the circuit diagram or when introducing the network list. When designing the circuit diagram, you can specify it in the Footprint setting item in the part properties dialog box, or you can specify the part package when importing the netlist.
Question 2: What is the difference between wires, flying wires and networks?
A: Wires, also known as copper film traces, are used to connect various solder joints for short, and are the most important part of printed circuit boards. The design of printed circuit boards is all about how to arrange wires. Another kind of wire related to conductor, often called flying wire, is also called pre-cable. Flying line is a kind of connection that is generated by the system according to the rules after the introduction of the network list and used to guide the wiring. There is an essential difference between flying wire and conducting wire. Flying wire is only a formal connection, it only shows the connection relationship between solder joints in form, and has no electrical connection significance. The wires are arranged according to the connection relationship between the solder joints indicated by the flying wires, which is a connection line with electrical connection significance. Different from wires, the network also includes solder joints, so when referring to the network, it not only guides the wires but also includes solder joints connected with the wires.
Question 3: What is the difference between the inner layer and the middle layer?
A: The middle layer and the inner layer are two confusing concepts. The middle layer refers to the middle board layer used for wiring, in which wires are laid; The inner layer refers to the power layer or the ground layer. Generally, this layer is not wired, and it is composed of a whole piece of copper film.
Question 4: What are internal network tables and external network tables, and what is the difference between them?
Answer: There are external network tables and internal network tables. The external network table refers to the introduced network table, that is, the schematic network table generated by Sch or other schematic design software; The internal network table is a modified network table which is used for wiring inside the PCB system according to the external network table introduced. Strictly speaking, these two kinds of netlists are completely different concepts, but readers don’t have to distinguish them strictly.
Question 5: What is the role of the netlist manager?
A: First, the introduction of network table, which is actually the process of loading the data of schematic diagram design into PCB of printed circuit board design system. All the changes of data in the PCB design system can be completed by Netlist Macro, which is automatically generated by comparing and analyzing the netlist file and the internal data of PCB system. Secondly, the network table manager can be used to directly edit the connection relationship among the components of the PCB system to form a network table.
Question 6: What is a class and what are the benefits of introducing the concept of a class?
A: The so-called class refers to a collection of units with the same meaning. Class definition in PCB is open to users, and users can define the meaning and composition of classes themselves. The introduction of class in PCB has two main functions: (1) Facilitating wiring f In the process of wiring circuit boards, some networks need special treatment, such as some important data lines. In order to avoid the interference of other components on the circuit board, it is often necessary to increase the safe distance between these data lines and other components during wiring. These data lines can be grouped into one class, and this class can be added to the rules when setting the automatic routing safety spacing rules, and the safety spacing can be appropriately increased, so the safety spacing of all data lines in this class will be increased during automatic routing; In the process of wiring circuit boards, the power supply and grounding line often need to be thickened to ensure the reliability of connection. The power supply and grounding line can be classified into one class. When setting the Width Constraint rule for automatic wiring, this class can be added to the rule, and the wire width can be appropriately increased, so the power supply and grounding line in this class will be widened during automatic wiring. (2) Easy to manage the circuit board assembly F For a large circuit board, there are many parts packaged on it, and there are thousands of networks, which are very messy. Using classes can easily manage the circuit board. For example, classify all the input networks in the circuit board, and when looking for an input network, just look it up in this input network class; You can also classify all the voltage limiting resistors in the circuit board. When looking for a certain voltage limiting resistor, you only need to look it up in this voltage limiting resistor category.
Question 7: How to add additional solder joints to the network?
Answer: You can add solder joints to the circuit board first, then double-click the solder joints to open the solder joint attribute setting dialog box, and select the appropriate Network in the net item in Advaced to complete the placement of solder joints.
Question 8: What is the use of inner layer segmentation?
Answer: The divided inner layer can be used to connect some important circuits, which can improve the anti-interference ability and protect important circuits.
Question 9: What is the function of copper plating and what should we pay attention to?
Answer: The main function of copper plating is to improve the anti-interference ability of the circuit board. If you want to coat wires or fill up tears on the circuit, then copper plating should be done last.
