Before we get into it, who uses data historian software and for what?
Data Historian software is primarily used by manufacturing companies who are trying to achieve maximum potential efficiency in their production process. You can track, store, and analyze trend data for machinery and equipment. This allows for many uses such as maintenance, quality assurance, compliance, and more.
Like previously stated in What is Data or Operational Historian Software?, historian software has some limitations and cons that may be bothersome to work around. The major ones shared were costing, difficulty to use/understand, and transferring of data.
Historian software, data storage, and recorder equipment is not inexpensive. That’s not to say that it won’t have great ROI when utilized correctly, but it may not be the best choice for every company. Recorder equipment may be the easiest to cost, costing around a few hundred dollars per logger/scanner for a single datum being tracked. Software is generally costed out per license which usually has a limited amount of users and tagged data available to track. You’ll can easily find yourself spending much more than some other available options.
Difficulty to Use/Understand
Historian software is generally known to have been driven by those who consistently use it. It has been developed for the plant engineers and machinery staff on the plant floor. The data is easily used for machine maintenance, but for further analyzation; it might need to be transferred or configured in another fashion. This requires transference…
Transferring of Data
A big limitation of historian software is in the way that it tags and tracks data. Although millions of data points are stored for usage; tagged data can only really be compared against itself which removes the context of the data. One can see the rise and fall in the productivity of a machine over time, but you can only assume so much without context.
In order to utilize the data to create context, one generally has to export or transfer the data into 3rd party software, such as excel. When doing so, you engage in moving large volumes of data from one place to another which can be a huge hassle.
Other Options to Data Historian Software
Traditional Chart Recorder
Traditional chart recorders in which mechanical pens create a line/trend graph on a paper chart in real time. This is a very inexpensive but inflexible option for recording data.
Advantages of Traditional Chart Recorders:
Instantly visible/presentable data
The chart recorder continuously draws the graph in real time. The recorder is generally attached to the machinery, within close proximity where users don’t need to take any further steps to view the data. This doesn’t solve the problem of data use by other departments, but it allow some simplicity in local use.
Mechanical parts cheap and easily replaceable
For the entire instrument, to track a gauge or reading on a machine; it could cost as low as $250 per unit. Compared to the tens of thousands of dollars easily spent per year a data historian, this pricing is extremely minimalist.
Produces Paper Documents for Storing
Many companies may want hard documentation for storing and saving historical data. Without needing any further steps, this is automatically what is created by chart recorders.
Disadvantages of Traditional Chart Recorders:
Need to fill consumable paper and ink
Although cheap and inexpensive in comparison; it is still a hassle and another step in the process to replenish consumable paper and ink on traditional chart recorders. With less automation; more steps can lead to more downtime and more opportunity for error.
Restrictions on Data Ranges, due to needing space on paper
Due to the available space on the paper, you have to decide upon the data range or “resolution” of the graph. If you have a large data range, you might be forced to use a higher resolution to fit the data on the paper; but you won’t be able to exact data points as easily. Lower resolution will have a more limited data range; you’ll have to decide upon the best practice for each specific instrument.
Only Produces Paper Documents for Storing
This makes it extremely inefficient for pulling historical data. Although very useful to see the current operating trend of the machine; unless the data had been transferred into a computerized log, you cannot easily make comparisons from past days/months/years. This type of data storage also makes it more difficult to share with other departments or decision-makers other than the local user.
Databases–most often relational databases–are the most common alternate option for Data Historian software. They differ in how the information and data is stored and able to be used. As stated in their name; they are generally used in creating relational and contextual comparisons between data.
Advantages of Databases:
Ability to Analyze Data Between Tags
Relational databases help create a background for data by being readily available to relate and compare multiple tags.
Data historians may be able to answer the question “How was the productivity of this machine this week compared to last week?”, which when used with other sets of data solve problems of efficiency; but relational databases can help answer questions like, “Which product is most commonly purchased among our largest customers and how many do we sell?”
Databases Are Easy to Read/Understand
Databases are commonly stored in tables, just like spreadsheets. This makes it extremely intuitive and very easy to read and understand since many other forms of data are displayed in similar fashion.
For enterprise level Data Historians; you can easily spend into the five or six-digits a year on licensing costs, not including data storage. You can easily get a SQL Relational Database at much more economical pricing.
Furthermore; a relational database may be able to sufficiently produce the same desired outcome of a data historian in and of itself. For a historian to be able to garner the same comparative data as a relational database would require additional software.
Disadvantages of Common Databases:
Takes a Lot More Storage Space
More data and analysis points creates larger volume of storage spaced used. Although probably still more cost-effective than historian software; this can be a point of contention.
Less Optimized Data for Quick View and Decision-Making on the Plant Floor
Relational databases can definitely be more efficient and useful for plant managers and other departments, but are generally less optimized for the plant floor for which historian software has evolved for. Plant-Wide Historians are specialized to record, store and retrieve large amounts of data quickly. Although you “may be able to sufficiently produce the same desired outcome of a data historian” with a relational database, when trying to pull from years of data with thousands of tags and present it, there will be a noticeable difference in the response.
Combination: Why Not Get Both?
Some companies opt-in to utilize both Historian Software AND Database Management Software. This is to try and further optimize and gain peak performance in their industry.
Advantages of a hybrid solution:
Best of Both Worlds
You can get the speed of writing, storing, and retrieving hundreds of thousands of tagged data that is recorded tens of thousands of times per second and also be able to gather relational and contextual data. Historian software is optimized for those on the plant floor, while the relational databases can be utilized universally.
Disadvantages of a hybrid solution:
Not Economically Viable
We’ve already discussed the high price point of using a data historian. Adding a relational database on top of that may not be the most cost-effective choice for many companies.
Convoluted Implementation and Data Sharing
Properly setting up both a traditional historian and relational database to work together can be difficult to get right. Also, though you are able to access information from both resources, cross analysis can be overly complicated when the data isn’t stringently managed across both platforms.
Big Data and IIoT
We are already on the verge of the future in being able to track millions of points of data by having universal connectivity and automated communication between machines. This could solve many of the stumbling blocks revolving around the storing, transferring, and even required analysis of said data.
The answer to the gaps in the Traditional Data Historian or Relational Database systems is not always to just “purchase both”. With the development of newer softwares and infrastructures, the ability to process and interpret machine data at higher speeds is only becoming more accessible and available in different ways.
In our next article, we’ll dive deeper into time series database management systems, and the advantages therein.