Industrial Training

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PLC Sink and Source?

PLC Sink and Source Course Powerpoint

Free PLC Source and Sink Course from Business Industrial Network
  • Please study the PLC Source and Sink Input infographic.
  • Please study the PLC Source and Sink Output infographic.
  • The left side of circuit shown is the Source device side. It is the most positive. If the source device has electronics it, it will be PNP. On the right side is the Sink device that is most negative and could be a NPN.
  • It might help to remember it this way. The Source is a positive voltage while the negative is Sinking into the ground. The Source switches positive while the Sink switches negative.
  • Electronic devices connected to the PLC I/O, have a Diode that only allows current flow one direction. Like a check valve! So pay attention to the device’s PNP or NPN wiring instructions.
  • Transistors have a Diode, referred to as an Emitter. A PNP transistor is wired Positive to Emitter, Negative to the Base, and Positive to the Collector. IC Chips have diodes and transistors in them too.
  • A Sinking transistor is an NPN which switches negative voltage on and off to the PLC DC source input card.
  • Relays have diodes too. The relay diode points opposite of current flow as it is to drain excess voltage. Electro-mechanical switches like pushbuttons allow current to flow in either direction, so they can be used in source or sink position.
The above powerpoint and text are part of the Free Online PLC Source-Sink Course at BIN95. <<<  Click to try 4 Free training interactives, see video, take online quiz and fully understand Sink and Source. All free.
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September 3, 2014 - Posted by | Education, Electrical, engineering, maintenance, PLC | , , , ,

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