This layer represents all the signal layers, and the components placed on it are automatically placed on all the signal layers, so we can use to connect the pads or through-vias Place quickly on all signal layers. Note: If you want to auto-route part or all of the circuits, then you need to define at least one forbidden wiring area on the forbidden wiring layer. Normally, we place a track or arc on the no-lamination wiring layer to form a closed area where automatic component placement and routing are allowed. In Protel 99 SE, in addition to the above working planes, there are the following working layers: Prohibit Wiring Layers are used to define the area where components are placed. When a PCB library component is placed on a printed circuit board, the component number and outline are automatically placed on the silkscreen. Silk screen layer is mainly used to draw the outline of the components, placing the number of components or other text messages. Protel 99 SE comes with 2 silkscreen, Top Overlay and Bottom Overlay. For different requirements of different solder pads, multiple rules can also be set in the solder paste protection layer. Similar to the solder layer, we can also enlarge or reduce the solder paste by specifying an extension rule. The solder mask functions similarly, but when using "hot re-follow" technology to mount SMD components, the solder mask is primarily used to create a silkscreen of the solder mask that is also positive. For different requirements of different pads, in the solder mask There are multiple rules that can be set and the Protel 99 SE also provides two layers of solder paste that are and. Generally, in order to meet manufacturing tolerances, manufacturers often require the designation of a solder mask expansion rule to enlarge the solder mask. The solder mask is negative and the solder placed on this layer Trays or other objects are copper-free areas. In Protel 99 SE there are 2 solder masks: and Bottom Solder. Masks (solder mask, solder paste protective layer) The mechanical layer is typically used to place information on board and assembly methods, such as circuit board physical dimensions, dimensional markings, datasheets, Hole information, assembly instructions, and other information.
![protel 99se mirror pcb component protel 99se mirror pcb component](https://i.ytimg.com/vi/--QBVHudplQ/sddefault.jpg)
There are 16 mechanical layers available in the Protel 99 SE:.
![protel 99se mirror pcb component protel 99se mirror pcb component](https://p.globalsources.com/IMAGES/PDT/B1188259294/pcb.png)
It also allows you to divide the internal power/ground plane into multiple sub-layers, ie each internal power/ground plane can have two or more power supplies such as +5 V and +15 V and so on. Each internal power/ground plane can be given an electrical network name, and the board editor automatically connects this level with other pads of the same network name (ie, electrical connections) in the form of pre-cords. The traces or other objects placed on these planes are copper-free, ie the working layers are negative * (negative). These working planes are dedicated to power lines and a ground lines. The Protel 99 SE supply 16 internal power / ground planes (referred to as the internal plane):. The signal layers are positive, ie the traces or other objects placed on these working planes are copper-clad areas. The signal layer is mainly used to place the components (top and bottom) and traces. Protel 99 SE provide 32 signal layers including TopLayer, BottomLayer, MidLayer1, MidLayer2. The working layers provided by the Protel 99 SE can be broadly categorized into seven categories: Signal Layers, Internal Planes, Mechanical Layers, Masks, Silkscreen Layers), Others (Working Layers) and System (Working Layers), execute menu commands during PCB Design Design / Options to set the visibility of each working layer.
![protel 99se mirror pcb component protel 99se mirror pcb component](https://www.7pcb.com/image/blog/how-to-export-gerber-files-from-protel-99se-7.png)
Only after understanding the functions of these working layers can the printed circuit board design be accurate and reliable.
![protel 99se mirror pcb component protel 99se mirror pcb component](https://image.slidesharecdn.com/protel99setraningmanualpcbdesign-120403084045-phpapp01/95/protel-99-setraningmanualpcbdesign-15-728.jpg)
Protel 99 SE offers several types of working layers. Before we proceed with the PCB design, the first step is to choose the right working layer.