May 27, 2018

Configuration of SITRANS P300 in SIMATIC Manager


Description:
It is a pressure measuring Instrument which is generally use for Absolute pressure measurement.
It can measure with accuracy ≤ 0.075%
It can work within limit of 1.3 bar pressure.
Silicon oil is used in Fluid filling in case in use of food industry edible oil is used because silicon is hazardous to human health.

 

Explanation:
First of all the mounting of instrument is done as per requirement.
When the pressure is applied in the valve of the instrument pressure is applied on Diaphragm so that it bends and piezoelectric plate is mounted on it.
When the piezoelectric plate bends the resistance is decrease in it so that when electric signal transmit on it difference can be shown on display that is measured pressure.
The readings in different units can be found using this instrument.
We can connect the equipment to the computer using PC/PD coupler and CP5711 via Profibus PA and Profibus PD can be analyzed on Simatic PDM. 

Schematic Diagram:


                                                                           
Configuration Steps:
Connect SITRANS P 300 to PC via Profibus and PC\PD Coupler.
Set the parameters of SITRANS P 300 using Mode button
Open SIMATIC PDM
File > New Project
View > Process Device Network View
Options > Set PG\PC interface [Select CP5711 Profibus 1<active>]
Project > Insert new object > Networks
Networks> Insert new object > Communication network > assign device type <Profibus network>
In profibus network Give the address of instrument i.e. 1-126 any number and assign instrument SITRANS P300
Open device > Open Project <upload \download to PG\PC>
Observe the result in process variable.

Conclusion:
Proper Commissioning of Device leads to accurate pressure measurement.
Position and Place of mounting is should be proper to get accurate output.
For Safety of the plant and workers this instrument is necessary.
We can conclude that by using this instrument we can maintain the pressure by setting higher and lower limit in equipment such as boiler, pressure vessel etc. and proper safety measures can be achieved.

                         
                                                                                                                 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

 

Network 1 :-The first rung connects SW1 and SW2 in series—mimicking an AND gate.
https://plcscadaacademy.blogspot.com/

Network 2 :- The second rung connects SW3 and SW4 in parallel—mimicking an OR gate.
https://plcscadaacademy.blogspot.com/