The Allen-Bradley 321156-A01 is a PCB Circuit Board Module. This board has been manufactured in layers with a top plastic layer and a bottom copper layer. This module is self-contained and can be found in a variety of devices including sophisticated computer systems. The substrate is a layer of conducting material that has been deposited or printed on the surface of an insulating board from the circuits. The individual electronic components which are found on the surface of the substrate are also soldered to the interconnecting circuits. Contact fingers which are found in strategic places along the edges of the substrate can function as connectors to the other external devices such as on and off switches or electrical devices.

The 321156-A01 module can perform multiple functions or one function such as being a signal amplifier. Each board exhibits a unique function. It has therefore been designed to function in whatever space it has been allotted. The spaces between the electrical conducting paths of this board are 0.04 inches.

The locations of the ports or holes in the 321156-A01 board for contact points or component leads have also been laid out. This information is, therefore, able to be translated into the instructions for the board’s automatic solder paster and for a computer-controlled numerical drilling machine. To detect flaws, electrical and visual inspections are also made throughout the manufacturing process. Some flaws are the result of the automated machines. For instance, components are sometimes shielded before the final soldering or sometimes they are even misplaced on the 321156-A01 board. Other flaws might also result because of excessive soldering paste.