Overspecifying or underspecifying device points needlessly drives up SCADA implementation costs.
By: Allan Evora
Article originally posted on CSIA Exchange.
I want to discuss some best practices around data acquisition and SCADA systems. The general theme is this: just because you can, doesn’t mean you should.
In today’s world, many devices and equipment we integrate are very smart and contain a wealth of information. One of the challenges we see that tends to drive up the SCADA implementation cost is overspecification of the types of points, point quantity, and frequency points are acquired.
Or… the opposite: not specifying in enough detail.
These challenges can lead to excess cost and perhaps missed expectations on SCADA implementation.
Overspecification for SCADA Implementation
Mission critical systems, like data centers, have smart meters that can provide several hundred points just from a single metered point in an electrical distribution system.
There’s often not enough time in the planning process for the engineering company who specifies the project to detail which of the 100 points are required to satisfy the end-user’s particular needs. Often, it’s because they don’t take the time required to learn the details from the end-user.
Is the customer doing energy reporting? Cost allocation? Measuring power quality? Are they just trying to calculate PUE? For each of those goals, the system integrator might pull a different set of points from the overall 100.
Boiled down, SCADA integration pricing is based on two basic things:
- Number of points: Because SCADA implementation pricing is based on a per-point quota, the number of points in the overall system can significantly raise the price. The bigger the system, the more points increase. It’s not uncommon for a big data center to have several hundred meters. Think of how many points that is!
- Overall work and effort required to integrate: A system with hundreds of thousands of points? That becomes quite an integration task to collect points, alarm them, and historize them. More integration labor = more cost.
During the design process, engineering companies should work closely with owners to really understand their end goals and tailor the points list to support those goals. Anything extraneous to those goals should be left out.
Underspecification for SCADA Implementation
Overspecification isn’t the only problem, however. Oftentimes we encounter the extreme, where the engineering company just gives us the type of device, but no guidance on the number of points or how it will be used.
In those cases, we try to set up an opportunity to meet with the owner, to help us understand what points need to be acquired, alarmed, and historized.
However, that’s not always possible. Visibility to the owner is often limited in construction projects. In a situation where the engineer does not specify the points required, and we don’t have access to the end-user, most of the time we’ll error on the side of caution and include more points than less.
Again, that leads to greater expense in terms of design and licensing.
Overly-High Data Acquisition Rates
Smart devices have the ability to communicate at extremely high data acquisition rates. But not everyone should poll their devices with high frequency just because they have the capability.
For example: in a typical non-mission critical system, such as a building automation system, you might only collect data every 15 minutes. Why? Things like temperature, humidity, and flow rates just don’t change that quickly.
But in a mission critical electrical distribution system, things can change within minutes or seconds.
Understanding how quickly you need to acquire points is extremely important. The size of the database, the size of the hard drive, and the amount of activity on the network all relate to how quickly you want to inquire or poll a particular piece of equipment.
If you determine you need a high rate of data acquisition, there’s a strategy you can implement to reduce cost and integration time.
Instead of setting up the device to acquire the data at a high rate all the time, do it based on a condition. You can set your data acquisition to poll equipment at a faster rate for a period of time after you start the motor because you want to see the inrush, or when power quality (sag or swell) strays outside normal boundaries. During normal operations, back that rate off.
This capability goes underutilized in many SCADA systems.
Looking to optimize the design and scale of your SCADA implementation? Contact us!
Allan D. Evora is a leading expert in control systems integration and president of Affinity Energy with over 20 years of industry experience working in every capacity of the power automation project life cycle. With a background at Boeing Company and General Electric, Allan made the decision to establish Affinity Energy in 2002. Allan is an alumnus of Syracuse University with a B.S. in Aerospace Engineering, graduate of the NC State Energy Management program, and qualified as a Certified Measurement & Verification Professional (CMVP).
Throughout his career, Allan has demonstrated his passion for providing solutions. In 1990, he developed FIRST (Fast InfraRed Signature Technique), a preliminary design software tool used to rapidly assess rotary craft infrared signatures. In 2008, Allan was the driving force behind the development of Affinity Energy's Utilitrend; a commercially available, cloud-based utility resource trending, tracking, and reporting software.
Allan has been instrumental on large scale integration projects for utilities, universities, airports, financial institutions, medical campus utility plants, and manufacturing corporations, and has worked with SCADA systems since the early ‘90s. A passion for data acquisition, specialty networks, and custom software drives him to incorporate openness, simplicity, and integrity into every design in which he is involved.