This document discusses programming languages for programmable logic controllers (PLCs) according to industry standards. It outlines 5 standard PLC programming languages: ladder diagram, function block diagram, sequential function charts, instruction list, and structured text. The document then focuses on ladder diagrams, explaining that rungs represent horizontal connections, rails represent vertical connections, contacts represent inputs, and coils represent outputs in ladder logic. It also covers normally open and normally closed contacts and provides ladder logic diagrams for 7 common logic gates: OR, AND, NOT, NAND, NOR, and XOR gates.

1. PLC
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PLC PROGRAMMING LANGUAGES
There are 5 languages that are considered to be standard
languages for use on PLCs, according to IEC section 61131–3.
1. Ladder Diagram (LAD)
2. Function Block Diagram (FBD)
3. Sequential Function Charts
4. Instruction List
5. Structured Text
LADDER LOGIC DIAGRAM (LAD)
the PLC Ladder program example looks like
What is RUNG? RAIL? CONTACTS? COIL?

2. PLC
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rungs and rails represent the real world electrical connections.
 Rungs are horizontal lines.
 Rails are vertical connections.
 Contacts represent the inputs
 Coils represent outputs.
NORMALLY OPEN (NO)CONTACT
NORMALLY CLOSED (NC) CONTACT
LAD LOGIC DIAGRAM FOR THE 7 LOGIC GATES
OR GATE

3. PLC
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AND GATE
NOT GATE
NAND GATE
NOR GATE

4. PLC
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XOR GATE