December 21, 2019

Open-loop and closed-loop (feedback) control


Fundamentally, there are two types of control loop;

1.     open loop control

2.     Closed loop feedback control.

In open loop control, the control action from the controller is independent of the "process output" (or "controlled process variable").

A good example of this is a central heating boiler controlled only by a timer, so that heat is applied for a constant time, regardless of the temperature of the building. (The control action is the switching on/off of the boiler. The process output is the building temperature).

In closed-loop control, the control action from the controller is dependent on the process output. In the case of the boiler analogy, this would include a thermostat to monitor the building temperature, and thereby feedback a signal to ensure the controller maintains the building at the temperature set on the thermostat.



A closed loop controller, therefore, has a feedback loop which ensures the controller exerts a control action to give a process output the same as the "Reference input" or "set point". For this reason, closed-loop controllers are also called feedback controllers.

The definition of a closed loop control system according to the British Standard Institution is 'a control system possessing monitoring feedback, the deviation signal formed as a result of this feedback being used to control the action of a final control element in such a way as to tend to reduce the deviation to zero.

Likewise, a Feedback Control System is a system which tends to maintain a prescribed relationship of one system variable to another by comparing functions of these variables and using the difference as a means of control.

The advanced type of automation that revolutionized manufacturing, aircraft, communications, and other industries, is feedback control, which is usually continuous and involves taking measurements using a sensor and making calculated adjustments to keep the measured variable within a set range. The theoretical basis of closed-loop automation is control theory.

December 20, 2019

Difference between discrete signals and analog signals:-


Digital Signal:-

Discrete (digital) signals behave as binary switches, yielding simply an ON or OFF signal (1 or 0, True or False, respectively).

Examples of digital signals:-Push buttons, limit switches, and photoelectric sensors are examples of devices providing a discrete signal.

Discrete signals are sent using either voltage or current, where a specific range is designated as ON and another as OFF.

For example, a PLC might use 24 V DC I/O, with values above 22 V DC representing ON, values below 2VDC representing OFF, and intermediate values undefined. Initially, PLCs had only digital I/O.



Analog Signal:-

Analog signals are like volume controls, with a range of values between zero and full-scale.

These are typically interpreted as integer values (counts) by the PLC, with various ranges of accuracy depending on the device and the number of bits available to store the data.

As PLCs typically use 16-bit signed binary processors, the integer values are limited between -32,768 and +32,767.

Examples of analog signal:-Pressure, temperature, flow, and weight are often represented by analog signals.

Analog signals can use voltage or current with a magnitude proportional to the value of the process signal. For example, an analog 0 to 10 V or 4-20 mA input would be converted into an integer value of 0 to 32767.

Current inputs are less sensitive to electrical noise (e.g. from welders or electric motor starts) than voltage inputs.

October 3, 2019

Create a Function for a valve Logic in siemens PLC

Learn how to create function (FC) in PLC using Simatic manager. Explanation using industrial valve example.


 https://instrumentationtools.com/create-function-for-valve-logic/

Creating FB block in simatic manager


Learn how to create FB block in Simatic manager. Explanation with example of industrial motor.



Click here for more detail.
 https://instrumentationtools.com/function-block-diagram-motor-control-logic/

DP master configuration in PLC

Learn how to configure profinet I/O system in PLC using Simatic manager.




Click here for more detail
 https://instrumentationtools.com/profinet-plc-configuration/

DP master system configuration in PLC

Configuring a PROFIBUS DP Master System in Siemens SIMATIC Manager

This guide outlines the steps to configure a PROFIBUS DP (Decentralized Peripherals) master system using Siemens SIMATIC Manager software. We will set up a PLC as the DP master and an IM module as a DP slave for communication.

Understanding the PROFIBUS DP Master System

A PROFIBUS DP master system is the central control unit responsible for managing communication with connected DP slave devices on a PROFIBUS network. It orchestrates data exchange, ensuring efficient and reliable communication between the PLC (master) and various I/O modules or field devices (slaves).


For this example, we will use a Siemens S7-300 PLC (specifically CPU 315-2 PN/DP) as the DP master and an IM 153-1 module as a DP slave device.

Configuration Steps in SIMATIC Manager:

  1. Configure the DP Master PLC:

    • First, open SIMATIC Manager and navigate to the hardware configuration.

    • From the hardware catalog, select and insert the CPU 315-2 PN/DP (or your chosen S7-300 CPU) into your project. This CPU will serve as our DP master system.

    • Once the CPU is added, the PROFIBUS DP master system line will be automatically created and associated with the CPU's integrated DP interface.

  2. Modify DP Master System Properties (Optional):

    • Click on the automatically generated DP master bus line in the hardware configuration.

    • In the properties window (typically at the bottom of the screen), you can modify various parameters of the DP master system, such as the PROFIBUS address, baud rate, and diagnostic settings, as per your project requirements.

  3. Add DP Slave Modules:

    • Right-click on the DP master line (the green PROFIBUS line) and select "Insert New Object" or drag and drop from the hardware catalog.

    • From the hardware catalog, navigate to the PROFIBUS DP > DP Slaves section.

    • Select and insert your desired DP slave device. For this example, choose an IM 153-1 module.

    • The IM module will appear connected to the DP master bus.

  4. Configure DP Slave Properties:

    • Double-click on the inserted IM 153-1 module to open its properties dialog.

    • Here, you can configure specific settings for the IM module, such as its PROFIBUS address, diagnostic behavior, and the I/O modules that will be connected to it. Configure these parameters according to your application's needs.

  5. Adding Multiple DP Slaves (If Required):

    • If your system requires more IM modules or other DP slave devices, simply repeat step 3 and 4 for each additional slave. All added slaves will appear on the same DP master bus.

  6. Understand I/O Module Slot Numbering:

    • For IM modules (like IM 153-1), the slot numbering for actual I/O modules connected to it will typically start from slot 4. This is because the initial slots (0-3) are reserved for internal communication or specific functions of the IM module itself, consistent with the S7-300 system's addressing scheme.


Modbus Communication between PLC and Energy meter


Learn how to configure and write PLC programs for Modbus communication between PLC and Energy meter.



Click here for more detail
 https://instrumentationtools.com/modbus-communication-between-plc-and-energy-meter/

Learn how to configure micro PLC hardware

Learn how to write the PLC program for micro PLC hardware configuration using software.


Click on image for more detail
 https://instrumentationtools.com/micro-plc-hardware-configuration/

September 14, 2019

Slot rules Siemens S7-300

Rack 0:
  • Slot 1: Power supply only (for example, 6ES7 307-...) or empty
  • Slot 2: CPU only (for example, 6ES7 314-...)
  • Slot 3: Interface module (for example, 6ES7 360-.../361-...) or empty
  • Slots 4 through 11: Signal or function modules, communications processors, or free.
Racks 1 to 3:

  • Slot 1: Power supply module only (for example, 6ES7 307-...) or empty
  • Slot 2: Free
  • Slot 3: Interface module
  • Slots 4 through 11: Signal or function modules, communications processors (dependent on the inserted interface module), or free.

May 3, 2019

DeMorgan’s Theorems

DeMorgan’s Theorems. Write the PLC program for DeMorgan’s Theorems using ladder language.




Click on image for more detail
https://instrumentationtools.com/demorgans-theorems-using-ladder-diagram/

Lows of boolean algebra


Lows of Boolean algebra. Explain Boolean algebra using ladder language.


Click on image for more detail





https://instrumentationtools.com/laws-of-boolean-algebra-ladder-logic/












April 20, 2019

Read temperature in the PLC



Analog scaling in S7-300 PLC

Analog scaling learning in PLC.Learn how to write PLC program for analog scaling.Learn how analog scaling is used in the PLC.



Click here for more detail
https://instrumentationtools.com/plc-program-for-control-valve-scaling/

PLC timer instruction


PLC timer used in PLC. Learn how to write timer instruction in the PLC.



Click on image for more detial
https://instrumentationtools.com/plc-program-for-iec-timers-ton-tof-tp-tonr-used-in-s7-1200/

March 19, 2019

Auto/Manual Operation of Roll down Shutters in industry

PLC based Auto/Manual Operation of Roll down Shutters in Industry. Learn PLC programming of this application using auto and manual mode.



Click on image for more detail
https://instrumentationtools.com/plc-based-auto-manual-operation-roll-down-shutters/

March 18, 2019

Portal view in TIA portal software.


Portal view in TIA portal software.


Problem Description:-
Explain Portal view in TIA portal software.


Diagram:-






Description:-
The TIA portal can manage all data in the project in single platform. There are two views in the software which can be change any time.

Two views of the TIA portal are 1) Portal view and 2) Project view.

Portal view:-

Task oriented and fast project starting facilities.

Project view:-

Hierarchical structure, all parameters and data available in single view.

In this view user can do following configuration,

Configure devices
Create project
PLC programming
Project migration
Change user interface language
Open project
Change the view of the software.





Note:-All explanation, representation are for learning purpose.

February 8, 2019

Run time advanced configuration in TIA portal


Run time advanced configuration in TIA portal

Open TIA portal and click on add new device



Select controller family from the list




Select CPU form the S7-1200 family



From the list select CPU 1214 AC/DC/RLY PLC





Select serial no 6ES7 214-1BG40-0XB0 from the list (this is for example only you ca select CPU which you have).



Click OK and done! PLC configuration.





Again add new device and open PC system family from the list



Select PC general from the list



Select PC station



Click OK



Add IE general from the hardware catalog.



Add it























Now add Wincc RT advanced from the catalog.




Select network view and check both IP address




Set the connection between two devices.Now RT advanced configuration completed.




Run time advanced configuration in TIA portal


Run time advanced configuration in TIA portal

Open TIA portal and click on add new device



Select controller family from the list




Select CPU form the S7-1200 family



From the list select CPU 1214 AC/DC/RLY PLC





Select serial no 6ES7 214-1BG40-0XB0 from the list (this is for example only you ca select CPU which you have).



Click OK and done! PLC configuration.





Again add new device and open PC system family from the list



Select PC general from the list



Select PC station



Click OK



Add IE general from the hardware catalog.



Add it























Now add Wincc RT advanced from the catalog.




Select network view and check both IP address




Set the connection between two devices.Now RT advanced configuration completed.