Exploring Supervisory Control And Data Acquisition (SCADA)

In the previous chapter, we learned how to monitor and control a machine through a Human-Machine Interface (HMI). An HMI is always close to the machine or Programmable Logic Controller (PLC) – that is, an HMI is always local to the machine, and it is basically meant to control a single machine/PLC. Here in this chapter, we will be learning about Supervisory Control And Data Acquisition (SCADA), which also provides a means of monitoring and controlling along with other functionalities, such as alarms, trending, and logging. However, the screen or PC for monitoring, controlling, or other functionalities can be in a remote place – that is, far away from the machine – and we can have one SCADA for more than one machine at different remote locations, unlike HMI. SCADA is an interesting and advanced aspect of industrial automation.

We are going to cover the following main topics in this chapter:

• Introducing...

Introducing SCADA

SCADA is a system consisting of various hardware and software that work together to monitor and control machines in an industrial process.

Supervisory control refers to a high level of overall control of several individual PLCs or multiple control loops.

Data acquisition refers to the gathering of information and data from a process that is analyzed in real time. Real-time data collection helps to reduce overhead costs, monitor an entire process, and increase efficiency.

SCADA system helps to collect, analyze, and visualize data from equipment or a machine and also provides a means of controlling the equipment or machine from a central location, which can be local or remote (that is, near the machine or far away from the machine).

SCADA is typically used to monitor and control geographically dispersed machines or devices. The following figure shows a simple SCADA system:

Figure 11.1 – A simple SCADA system showing SCADA...

Understanding the functions of SCADA

The meaning of SCADA already implies its major functions. The following goes into detail about what a SCADA system does:

• It controls industrial processes either locally or remotely. Switching on or off a machine, increasing or decreasing setpoints, and so on are control functions that a SCADA system can be programmed to perform.
• It collects data (acquires real-time data) from a field or machine, which provides a status indicator to the operator or process engineer for monitoring.
• It enables a process engineer to have a bird’s-eye view of an entire plant, which can consist of various machines/devices at different geographical locations.
• It generates alarms when abnormal conditions occur within a process. It can trigger alarms that can be in the form of audible sounds, lights, emails, SMS, or other forms when something is wrong in a process.
• It records events (data logging).

Next, let’s take a look at the...

Exploring the applications of SCADA

The following are a few applications of SCADA:

• Water treatment plant: SCADA helps in monitoring reservoir levels, pump operations, water flow, and lots more, and also helps in controlling pumps and other equipment in a plant.
• Power generation and distribution: A SCADA system helps to monitor and control power generation and distribution networks. SCADA can monitor various equipment in substations and also send a signal to control equipment in a remote location to switch ON or OFF a breaker.
• Manufacturing: SCADA controls industrial automation equipment used in the manufacturing of various goods. It also monitors manufacturing processes.
• Building and facility management: SCADA is used by facility managers to monitor and control lighting, Heating Ventilation and Air Conditioning (HVAC), and so on.
• Traffic light: SCADA is used to monitor traffic lights such as failure detection, incorrect signals, and lots more. It is also used...

Overviewing the SCADA hardware

The hardware components of a SCADA system include the following:

• Field devices: These are sensors, transmitters, and actuators that are directly connected to the machine or plant and generate a digital or analog signal for monitoring. Sensors or transmitters are for monitoring machine status or parameters, while actuators are for carrying out control action on equipment or a machine.
• Remote station: This can be a PLC or a Remote Terminal Unit (RTU). It is installed at a remote site where the machine or equipment to be monitored or controlled is located. Field devices (sensors, transmitters, and actuators) are connected to remote stations (a PLC or an RTU) to allow monitoring and control from the host computer at a remote site via a network. It gathers data through the sensors connected to it and transfers them to the host computer via a network. It also transfers an electrical control signal from the host computer to the actuators connected...

SCADA software

This is software that can be used to create the interface (GUI) required to monitor and control the industrial equipment and perform all necessary configurations. It is usually installed on a central host computer, where monitoring and control operations will be carried out.

Common SCADA software includes the following:

• WinCC by Siemens
• FactoryTalk View by Rockwell Automation
• InTouch by Wonderware
• iFix by General Electric
• Citect SCADA by Schneider
• mySCADA

We are going to use one of the preceding SCADA software (mySCADA) in this chapter to learn how SCADA works, and to understand its basic configuration and wiring for a simple system.

mySCADA is powerful SCADA software that runs on Microsoft Windows, macOS, and Linux. It supports various PLCs, including S7-1200, S7-1500, S7-300, S7-400, ControlLogix, CompactLogix, Micrologix 1200, Micrologix 1400, Micrologix 1500, SLC 500, PLC 5, Omron PLCs, and Melsec-Q.

It basically consists...

Downloading and installing mySCADA software

Let’s start by learning how to download the software, as it will be used in the SCADA project in the Interfacing SCADA with an S7-1200 PLC using mySCADA software section of this book.

Downloading mySCADA

We will perform the following steps to download the two pieces of software (myDESIGNER and myPRO) to our PC:

1. Visit www.myscada.org and click on RESOURCES:

Figure 11.2 – The home page of mySCADA.org

2. Click on Downloads:

Figure 11.3 – The RESOURCES page

3. Click on register or log in here, fill in the necessary details, and click Register:

Figure 11.4 – The DOWNLOADS page

4. You should have the following screen if everything is okay:

Figure 11.5 – The welcome message

5. Check your email for a message from mySCADA, which contains the link to access your...

Interfacing SCADA with an S7-1200 PLC using mySCADA software

We will learn how to configure a simple SCADA in this practical project. You will have a basic understanding of how to monitor and control a machine using SCADA.

We will be using Siemens S7-1200 as our remote station. Hence, TIA Portal will be used for the configuration and programming of the PLC (S7-1200).

Let’s get started:

1. Start TIA Portal, click on Create new project, and type the project name (for example, SCADA-PRACTICE), as shown in the following screenshot. Click Create:

Figure 11.9 – Creating a new project

2. Click on Configure a device:

Figure 11.10 – A new project created in the PORTAL view

3. Click on Add new device and select Controllers from the device list. Expand SIMATIC S7-1200 | CPU | CPU 1211C AC/DC/Rly and select the order number of your PLC – for example, 6ES7 211-1BE40-0XB0 – depending...

Summary

Congratulations! You have successfully completed another chapter of this book. Good job! This chapter gave a good explanation of SCADA in a very simple way. The SCADA hardware (field devices, remote stations, communication networks, and master stations) and software was well explained. You should be able to download and install mySCADA software on your own by following the step-by-step guide. The last section is a very interesting part that shows you how to create a simple SCADA screen. The necessary configuration for monitoring and control was outlined in the step-by-step guide.

The next chapter is another interesting chapter that will give you the fundamentals of process control in various industries.

Questions

The following are questions to test your understanding of this chapter. Ensure you have read and understood the topics in this chapter before attempting the questions:

1. SCADA is an acronym for _______________________________.
2. RTU is an acronym for _____________________________.
3. __________________ refers to the sensors, transmitters, and actuators that are directly connected to a machine or plant and generate a digital or analog signal for monitoring.
4. _________________ refers to the master computer that runs SCADA software that provides the graphical presentation of a system.
5. ________________ is usually installed on a master station to create an interface (GUI) required to monitor and control industrial equipment, and perform all necessary configurations.