Is SCADA a Data Historian?

Over the past few articles, we have been covering the basics of a system called SCADA. How it works, what it does, and what components make it up. 

The Historian is an integral part of a SCADA system and responsible for storing site data. Let's start by defining some terminology, then move on to how historians work, what features they have and what uses you can get from them. 

This article will try to clear up what the similarities & differences between SCADA, HMI, Historians, Alarming and Reporting are.

SCADA is a system that monitors and manages all the devices, such as inverters and trackers. It also has an HMI interface and historian in order to keep track of important information.

HMI stands for Human Machine Interface and is the interface that allows operators to have a bird's eye view on plant data. It also allows them to enter commands to the PPC. Alarms and information from HMI SCADA consoles are helpful for operators to make faster and better decisions. You can visit our website if you'd like to learn more about the different variations of this product.

The Data Historian is a required part of SCADA installations where it stores, logs and reports on the historical data for the plant. This allows operators & stakeholders to keep an eye on the history of your plant's performance by looking at data from previous times.

A manufacturing data historian can also generate reports. This lets them show different sets of data over different periods of time, which helps the user to better understand what happened at the plant.

How does a local historian fit into a SCADA system?

A local historian is a system that runs locally on the plant's network. It interacts with the SCADA network and in principle always has a data link to the HMI software. The historian transforms the data from the HMI software into documents which are usually text files that are stored on a storage medium.

There are also cloud-based historian systems, where data is offsite on Internet-based servers, providing protection against disasters.

A historian is recommended or required as a part of a local SCADA system

Empowered Automation recommends that if your plant already has a SCADA system, you should also have a historian installed locally.

A lot of owners and operators of facilities need a remote cloud-based system to store data offsite, where it is safe. They also need the capability to pull information from their own devices, even if they have no internet connection at all. In order to find out what your business was doing in the past, you can either go back and look at archived data or ask a historian for help. A local historian could also be useful if you have needs such as tracking activity, analyzing reports or storing other documents.

We are often asked, "What edge does a historian bring to DAS and SCADA?

A DAS instead of SCADA system typically requires less data storage, which means there is no need for a historian in this specific environment. This doesn't mean there's not a need for them - regulations and requirements still exist! Historians are important for any DAS site. Most DAS sites get it by using a cloud-based historian, but some do also require a local historian in order to get the best performance and content quality.

They need this for sure. But because data storage doesn't happen onsite, the data is often stored long-term through a third-party cloud historian platform, which means it's all offsite so they don't have worry about expensive hosting costs or corruptible hardware. This data can be marked for short-term storage, so it doesn't take up space on your servers. A local historian will hold data for longer and take up your space

What kind of analytic data would you like to track?

A smaller site may not need to be closely monitored because of their simpler DAS, but a larger site with SCADA requires more analytics and reports in order to operate smoothly. A historian who is also an expert in the local region and knows how to analyze data and interpret it in a variety of ways can make all the difference.

What kind of computer/hardware and software do you need to run local historian?

Two main factors in historian hardware requirements are:

• The hard drive space
• The historian is installed on a machine with great processing power.

The amount of data that can be stored with a hard drive depends on the size; the more space, the more data can be saved for later, and vice versa. The processing power determines how much data can be processed by the historian at a time.

Every device & piece of equipment at a site can send data that the SCADA system can collect and analyze, whilst the historian logs and stores it. As a result, there are many data points. The more devices there are at a facility, the more points that need to be monitored!

Historical records software is typically tied to the site's keywords or tags. The more tags, the bigger and more expensive the software will be. For example, you might choose a different level of software licensing based on how many times your site is mentioned on other sites (50,000 tags versus 10 million).

Historian platforms vary in the formats they can be reported in. The kind of space a brand or type of historian software fills isn’t evident until that decision is made. For instance, some historians require proprietary reporting tools, but Empowered allows you to use any reporting tools of your choosing.

What are some common historian capabilities and features?

There are 3 common capabilities

1. Queries: Which lets the historian pull relevant raw data from the system and put it into a spreadsheet. Different approaches can be used depending on what the historian offers support for. There you'll find multiple custom database functions that provide calculated information. These include the average of numbers for a certain period, the ranges for minimums and maximums and more.
2. Trends: Here you can see our site performance plotted over a 5-year period. You'll be able to see the trends in your data and take the necessary action to improve it.
3. Reports: As a core capability, this is what combines the two. The historian can put raw data and trends into a report that runs on a schedule (once a month for example).

What is the difference between a local database and a true historian?

One example of this is Microsoft SQL, which stands for Structured Query Language. If you want to access the data in this kind of database, you'll have to use their language - which means putting in more effort than with a traditional database. Getting the information that's in there and turning it into something more easily digestible is a process that will be require more work on your end. However, with Empowered Historian we do all the heavy lifting for you. We put the data in an open format to be used by 3rd party software applications.

A true historian uses a historical database The historian uses proprietary software to log the data and costs more than logging to a free open database.

How often can data be logged within the historian?

Usually, data is logged at one-second intervals. However, there are some limitations when it comes to this type of measurement.

If devices/equipment can't report data at a one-second interval, the data will be reported at an average of "one second" and the historian will interpolate. The available hardware capacity is also something to keep in mind. Ideally, the site takes one-second data from the historian over two years. But if there is not enough storage available then five second data would work or 15 seconds if needed.

Empowered Data Historian will allow you to log continuously, based on time, or an event.

How can local historian software be used to help troubleshoot machines?

The historian tool is useful for identifying time-based trends in data. By looking at trends over days, weeks, and months, operators can spot patterns that need to be addressed. This helps prevent problems from getting worse before the issue can be resolved. If a device malfunctions, its recorded data could be used to identify and fix the problem. If there is no recorded data, it would be very difficult to troubleshoot and identify the specific issue.

What is the difference between performance analytics and historian data?

Historian data is raw data that comes in from site equipment. You might want the filtered info about trends & amp; averages over time. Creating custom queries and formulas can turn that raw data into calculated data.

Performance analytics use data from your site to generate insights into how it is performing. There are many different types of performance analytics software out there.

Does local historian software help with SCADA implementation?

It does! The historian covers a lot of ground throughout the commissioning process, ensuring that when we transition to live-state, all the kinks have been ironed out. For example, if we need to make some minor tweaks to the scaling or offset for a data point, we can use the Historian so that these changes are tracked accurately over time.

When testing for site functionality, a historian may be linked to the control portion of the site to ensure that it's working. When you're tuning and tweaking power controller logic, one important thing is maintaining good site functionality. Data analytics allows us to look at points in the past to determine whether any changes were made to some of the controller's settings.

We use this when tuning, so that we can keep track of historic information and compare it with current data."

Helps with performance testing or capacity tests

The performance and capacity tests are often run by the owner, who may ask the SCADA integrator to pull in historical data. This is to track any issues that arise and help resolve them as quickly as possible. Learn more about HMI SCADA.