By Kartik Pandav
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May 27, 2018
Configuration of SITRANS P300 in SIMATIC Manager
By Kartik Pandav
May 19, 2018
Latching Cercuit (Controlling The motor by pressing Start Stop Button)
Latching Circuit for Motor Control – Ladder Logic Application
Objective
To control a motor using
momentary Start and Stop pushbuttons. Once the motor is turned ON using the
Start button, it should remain energized (latched) even after the Start button
is released. The motor should turn OFF only when the Stop button is pressed.
Working Principle
- Start Button (I0.0):
A normally open (N.O.) push-button. When pressed, it energizes the motor. - Latching Logic:
The motor output coil (Q0.0) is fed back into the same rung to maintain the ON state, creating a memory or latching loop. - Stop Button (I0.1):
A normally closed (N.C.) push-button. When pressed, it breaks the circuit and stops the motor by de-energizing Q0.0.
Ladder Logic Program
Explanation
- Rung 1 energizes the motor output Q0.0 when all
conditions below are true:
- The Start button (I0.0) is pressed.
- The Stop button (I0.1) is NOT pressed (i.e.,
remains closed).
- The motor output (Q0.0) is used in a parallel
branch to maintain the circuit (latching).
- The latching branch ensures that once Q0.0 turns
ON, it holds the rung logic true even if the Start button is released.
- Pressing the Stop button opens its normally
closed contact, breaking the circuit and turning OFF Q0.0, thereby
stopping the motor.
AND & OR Gate Opertion in Ladder language
AND
& OR Gate Operation Using Ladder Logic
🎯 Objective:
Control
two lamps using four switches through:
- AND Gate logic (series connection)
- OR Gate logic (parallel connection)
📘 Application Description
We have
four input switches and two output lamps. Two control scenarios are
implemented:
✅ Task 1 – AND Gate Logic (Series Connection)
- Inputs: SW1 (I0.0), SW2 (I0.1)
- Output: Lamp 1 (Q0.0)
- Logic: Lamp 1 turns ON only if
both SW1 and SW2 are turned ON.
- Equivalent to: Q0.0 = I0.0 AND I0.1
✅ Task 2 – OR Gate Logic (Parallel Connection)
- Inputs: SW3 (I0.2), SW4 (I0.3)
- Output: Lamp 2 (Q0.1)
- Logic: Lamp 2 turns ON if either
SW3 or SW4 is ON.
- Equivalent to: Q0.1 = I0.2 OR I0.3
🧠Input/Output Assignment
|
Device |
Address |
|
SW1 |
I0.0 |
|
SW2 |
I0.1 |
|
SW3 |
I0.2 |
|
SW4 |
I0.3 |
|
Lamp 1 |
Q0.0 |
|
Lamp 2 |
Q0.1 |
