SCADA explained

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SCADA explained
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SCADA explained

– by Albrand Veldhuizen, 15-12-2020

SCADA is an acronym for Supervisory Control And Data Acquisition, a software layer designed to centrally control and acquire data from all assets within a system…  Which in our case, revolves entirely around HVAC.  

The main benefits that SCADA provide are control and the ability to use alarms. You become the supervisor of the entire HVAC system, with access to all relevant data just a click or swipe away. Airflows, chiller capacity, temperatures in cabins, alarms and trends from up to two years in the past, you name it.

This blog explores the concept of SCADA by answering the following questions:

  1. When was SCADA invented?
  2. How does it work?
  3. Why is SCADA important?

1. When was SCADA invented?

SCADA has its origins in the oil & gas, utility and manufacturing industries. These sectors used to rely on plant personnel to monitor and control industrial processes like pushing buttons and turning valves and dials for analogue systems. Plant production processes therefore needed to be manned day and night.

Over the course of time humans were replaced by relays, timers and controls to assist in the supervision and control of processes. Mainframes communicated on a very local level and little by little more machines were connected to each other. The first real SCADA program came with the early PLCs back in the 1970s.

A PLC or Programmable Logic Controller is a small industrial computer with different I/Os, input and outputs. It has a processor running inside and a custom program which it follows by reading the input signals and changing outputs based on the program conditions.

2. How does SCADA work?

In short, SCADA is a graphic digital control system architecture that connects all PLCs and collects, examines and processes data in real time.

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At level 0 you will find field devices such as temperature, pressure and flow sensors, plus three-way valves, fan motors, pumps and other final control elements such as fire dampers and air valves.

Level 1 devices are the input and output modules such as PLCs but also local operator devices like touchscreen HMIs (Human Machine Interfaces).

On level 2 we find the SCADA computer which pulls all the information from the system and displays it to the supervisor via an advanced mimic program.

3. Why is SCADA important?

A SCADA system offers many advantages, including major manhour savings due to its central geographical control element. Everything remains manageable on a ship with one or two AC units and a chiller centrally placed within the vicinity of the engine room. But on a large vessel, with more than a dozen AC rooms divided all over the vessel, controlling and supervising all HVAC systems from a central spot in the control room is a genuine delight.

And SCADA offers more possibilities such as simultaneously changing multiple setpoints or switching whole decks into energy-saving mode with one swipe. The more advanced the SCADA system, the more data you get, like animated displays of AC units showing all parameters in real time. With the adoption of a SQL database the SCADA system is able to save data for up to two years. This gives easy access to historical trending and alarms, and is a powerful tool for troubleshooting and maintenance.

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The future of SCADA

The software behind SCADA is still advancing, with every iteration becoming smarter and offering more possibilities. Future iterations can be programmed in such a way that they read the HVAC system and its parts, making suggestions on how to solve an alarm or schedule maintenance stops and spare part replacements. Such a self-diagnosing system enhances the ease of operation for the installation.

The internet of things (IoT) is also opening up new possibilities. Instead of monitoring the HVAC system of one vessel, you can control the systems of an entire fleet from a centralised control centre on shore. This does of course mean more level 0 devices will need to be placed and wired.

Like to know more about SCADA and which options could be implemented on your vessel? Contact one of our engineers.

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Albrand Veldhuizen | Commissioning Engineer

Albrand has been working at Heinen & Hopman since 2006. He has worked himself up to the position of Commissioning Engineer and nowadays he is stationed at one of the largest yacht builders in Germany. During his many years working onboard numerous luxury yachts, he has developed a great expertise in HVAC systems for superyachts.