Video summary

Belajar Pemrograman PLC dari Nol Mudah dan Praktis !!

Main summary

Key takeaways

Educational

Main ideas & concepts covered

Goal of the video

  • Introduce PLC (Programmable Logic Controller) learning for beginners.
  • Start from foundational control system concepts.
  • Connect those concepts to relay-based control.
  • Finish with a simple example case study solved using both relays and PLC programming.

Why PLC for beginners?

  • The instructor argues PLC becomes easier if you already understand relay-based ladder/schematic logic.
  • Reason: the logic/program representation is similar (ladder/schematic diagram).

Control system structure (core framework)

1) Input

  • Typically buttons and sensors.

2) Control / Logic

  • Implemented via either:
    • Relay-based control (hardwired logic)
    • PLC-based control (software/programmable logic)
  • Includes logic and sequential concepts as the basis for operation.

3) Output

  • Typically electrical/electro-mechanical outputs, such as:
    • Indicator lamps
    • Motors
    • Electro-hydraulic/electronic actuators

Terminology / representation

Logic diagram method

  • Uses a schematic/ladder diagram approach (subtitles describe it as a “leader diagram / schematic diagram”).

Wiring diagram method

  • Uses standard symbol language for:
    • buttons
    • sensors
    • relay contacts
  • This helps represent hardware consistently.

Hard-wire vs soft-wire

  • Relay control (hard-wire)

    • Logic is implemented using cables/wiring.

  • PLC control (soft-wire)

    • Logic is implemented in software.
    • Wiring connects inputs/outputs to the PLC.

Case study used throughout (logic problem)

Purpose

  • Build understanding of:
    • the purpose of wiring
    • why ladder/logic diagrams look the way they do
  • Start simple.

Functional requirement: lights control

Inputs

  • Button 1
  • Button 2
  • Button 3

Outputs

  • Lamp 1
  • Lamp 2

Behavior

  • When Button 1 is pressed:
    • Lamp 1 and Lamp 2 turn ON
  • When Button 1 is released:
    • Lamp 1 and Lamp 2 remain ON
    • (This implies a latching/locking (“locking circuit”) behavior.)
  • When Button 2 or Button 3 is pressed:
    • Lamp 1 and Lamp 2 turn OFF

Relay-based solution (three methods)

The instructor presents three relay circuit methods (all producing the same overall behavior). The focus is on:

  • implementing the locking circuit
  • how normally open/normally closed button contact types affect both the circuit and later PLC programming.

Relay symbols and assumptions mentioned

  • Normally Open (NO) push button

    • Normal (not pressed): open
    • Pressed: closes

  • Normally Closed (NC) push button

    • Normal (not pressed): closed
    • Pressed: opens

  • Relay (K)

    • Has a coil (activation)
    • Contacts can be NO or NC depending on relay state

  • Indicator lights

    • Represent outputs (Lamp 1, Lamp 2)

Method 1 (relay solution)

  • Core idea: Button 1 energizes relay K1, and a parallel locking contact keeps K1 energized after Button 1 is released.

Logic described

  • Button 1 is NO.
  • Pressing Button 1 energizes relay K1.
  • A locking circuit is formed by using a K1 contact in parallel with the path from Button 1.
  • After K1 locks in, the K1 locking contact closes, keeping the coil ON even if Button 1 is released.
  • Button 2 and Button 3 are used to turn the lamps OFF (shown as branches that break/interfere with the locking so the relay unlatches).

Result

  • Lamps stay ON after Button 1 release.
  • Lamps turn OFF when Button 2 or Button 3 is pressed.

Method 2 (relay solution; “a little longer”)

  • Core idea: Use additional relays (K1, K2, K3) to represent separate button effects, then re-draw/interpret contacts so the latch behavior matches the requirement.

How it’s described

  • Press Button 1 → K1 becomes active
  • Press Button 2 → K2 becomes active
  • Press Button 3 → K3 becomes active
  • Conceptually, the circuit is re-drawn by replacing the “direct button” logic with relay contact logic (using NO/NC behavior appropriately).

Teaching point

  • The instructor emphasizes understanding the transition from relay circuit 1 to circuit 2 to avoid confusion when moving to PLC logic.

Method 3 (relay solution; adjusts contact types)

  • Core idea: Keep the relay framework but change where/which buttons are interpreted as NO vs NC so the same behavior is achieved.

Key adjustment

  • The difference is in the NO/NC arrangement in the “blue” portion of the circuit (as described in the subtitles).

Result

  • Same functional behavior:
    • Button 1 latches ON
    • Button 2 or Button 3 unlatches OFF

PLC introduction and mapping from relay logic

PLC hardware shown

  • OMRON PLC CP1E (subtitles reference a model like CP1E N20DRD).

PLC components explained

  • Input section
    • where button signals connect
  • CPU (Central Processing Unit)
    • runs the program (“brain”)
  • Output section
    • drives outputs (described as “output relay”/transistor mechanisms, e.g., mentions a code like T1)

Key transition idea

  • Ladder/schematic-style relay logic diagrams map to PLC logic.
  • Wiring changes:
    • from hardwired relay circuits
    • to PLC input/output addressing.

PLC-based programming methodology

Two PLC methods are described, analogous to the relay “method” variations, mainly determined by whether buttons are treated as NO or NC.

PLC setup and addressing (as described)

  • Power supply: DC 24V
  • Input addresses (channel 0):
    • Button 1 → K1 → input address 0.00
    • Button 2 → K2 → input address 0.01
    • Button 3 → K3 → input address 0.02
  • Output address:
    • Lamp control → K4 → output address 100
    • (Drives Lamp 1 and Lamp 2 in the example.)

Ladder/logic rules shown

  • The program uses ladder-symbol conventions:
    • Normally Open contacts written in PLC program style
    • Normally Closed contacts written using different PLC notation
    • The coil/output (energize output relay) uses the corresponding symbol/brackets

PLC Method 1 (based on NO contact arrangement)

  • Assumption: Buttons are treated as Normally Open in the PLC logic.

Conceptual steps

  • Create ladder rungs so:
    • Button 1 contact (0.00) can turn ON the output (K4 / 100)
    • a self-holding / locking contact keeps the output ON after Button 1 release
    • Button 2 and/or Button 3 interrupts the holding so output goes OFF when pressed

Outcome

  • Mirrors relay locking behavior, implemented in software.

PLC Method 2 (change Button 2 and 3 to NC)

  • Assumption: Button 2 and Button 3 are wired/treated as Normally Closed.
  • Button 1 arrangement stays as in the other method.

What changes

  • Input and output addresses remain the same:
    • inputs: 0.00, 0.01, 0.02
    • output: 100
  • Only the ladder logic changes:
    • Button 2 and Button 3 use NC logic instead of NO

Outcome

  • Same functional behavior:
    • Button 1 latches ON
    • Button 2 or Button 3 turns OFF

Notes emphasized by the instructor

  • Wiring changes (NO/NC) must correspond to:
    • program changes (NO/NC ladder contact representation)
  • PLC logic must match the actual contact types used in wiring.

Main lessons conveyed

  • PLC logic is easier after relay ladder logic because the conceptual diagram structure is similar.
  • In control systems:
    • Inputs (buttons/sensors) feed the PLC
    • The PLC CPU runs logic/sequential programs
    • Outputs drive actuators (lamps/motors/etc.)
  • Latching/locking behavior is a key recurring pattern:
    • Relays: achieved using parallel self-hold contacts
    • PLC: achieved using self-holding in ladder logic
  • NO vs NC matters:
    • It changes both the relay circuit behavior and the PLC ladder contact types you must use.

Speakers / sources featured

  • Eko Aris — Mechatronics Engineering Technology Study Program, Vocational Faculty, Sanata Dharma (Darmat) University, Yogyakarta.

Original video