Implementing a Secure I/O Table for an Automatic Door Using Siemens S7-200 PLC 'spartacus 1960'

Introduction

-------

In modern industrial automation, ensuring secure communication between devices is crucial. One effective way to achieve this is by implementing the Modbus RTU (Remote Terminal Unit) protocol within Programmable Logic Controllers (PLCs). In this article, we will focus on setting up a secure I/O table for an automatic door using Siemens S7-200 PLC.

Hardware Requirements

----------------

* A Siemens S7-224 CPU Module from the 1500 series of Allen Bradley's Logix family.

* An industrial-grade motion sensor (e.g., Pepperl & Fuchs or Schneider Electric) to serve as the input device for detecting movement near the door.

* Twisted pair cables with suitable connectors and shielding for reliable communication between devices.

Software Requirements

----------------

* Siemens Simatic WinPLC 5.3 SP2 or higher version of PLC programming software (free download from 'www.siemens.com'(http://www.siemens.com)).

* Modbus RTU Master/Slave library compatible with the chosen PLC firmware and development environment.

Step-by-Step Configuration

--------------------------

### Step 1: Connect Hardware Components

1. Connect one end of a twisted pair cable to the input terminal (e.g., IN0) on the motion sensor.

2. Route the other end of the same cable to an available DI (Digital Input) module in your PLC rack, making sure not to damage any internal components during installation.

### Step 2: Configure I/O Table

1 Open Siemens Simatic WinPLC 5.3 SP2 or higher version and create a new ladder logic program called 'AutoDoor'.

2 In the Device-Connection window of the Project Manager, double-click on your CPU (e.g., 'S7-224-CPU226-0PNR').

3 Double-click again in the newly opened dialog box under Peripheral 1/In to open the Input Configuration page.

4 Click 'Add' and select 'Digital In' from the drop-down list. Name this new digital input as DI_01.

### Step 3: Configure Modbus RTU Master

1 Open your Simatic WinPLP5 project again and double-click on Tools -> Peripheral/Bus Config in the menu bar.

2 Under Bus Configuration, click 'Add' to add a new bus profile called 'ModbusRTUMaster'.

3 Select MODBUS RTU as the communication protocol from the drop-down list. Set Slave ID = 1 (default), Baud rate = 9600 baud/s and Data bits/Parity/Stop Bits according your requirement.

4 Click 'OK' to save changes.

### Step Read More...

Spartacus 1960