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5. Programmable Logic Controller Deconstruction

Detailed photos attached in files/images and links The device we deconstructed and analyzed was a Programmable Logic Controller (PLC). Our team decided to deconstruct a PLC because members of our team had just learned about PLC’s in our electrical engineering courses. Seeing an opportunity not only to apply newly learned knowledge but to learn more about the internal components of a circuit, we decided to take apart a PLC and analyze the components in the circuit to see what components make up a PLC and what those components are used for         Inside the PLC we deconstructed were mostly resistors, capacitors, and LEDs. The rest of the components are logic gates, buffers, transistors, switches, diodes, a dual differential line driver, and a dual differential line receiver. Of those components, only two were Texas Instruments components. They were the Dual Differential Line Driver (SN75158P J832X2) and the Dual Differential Line Receiver (UA9637ACP J631A2). According to our research, a dual differential line driver operates by taking two inputs and giving four outputs, two pairs of a non-inverted and an inverted signal. A dual differential line receiver receives the signals from the driver and converts them to two outputs. The purpose of the line driver in this circuit is to provide a positive and negative output. This output is feeded to the line receiver and it provides a high and low output voltage. In conclusion, the importance of the two TI components in the PLC we took apart was to drive certain components in the circuit according to the needs of the controller.