Making things easier with a small user friendly DCS

The Freelance distributed control system (DCS) provides the functionalities users need to improve performance, while eliminating complexity and remaining a robust, scalable and user-friendly control solution at an attractive price.

Use of different standalone PLCs

For small and less complex automation tasks with only few signals, standalone PLCs (programmable logic controllers) have often been used, because process control systems or DCS have been too expensive for these tasks. In the process industry, such as oil & gas or chemical industry, many control tasks, e.g. compressors, centrifuges or steam generators, have been automated as PLC-based package units, leading to variety of different control systems and tools.

But the use of different PLCs comes with some disadvantages: several tools cause higher training effort and lead to increasing complexity, but without adding value. In particular during maintenance, minor changes may cause significant expenses caused by cross-influences from different systems that require manual adjusting. In addition, the differences in visualization and operation as well as the individual alarm concepts used by the various manufacturers can, in extreme cases, even affect the availability and safety of the application and the total plant negatively. Furthermore, the flexibility of the maintenance personnel is reduced because not all users may be familiar with all tools. Procuring and storing spare parts for many different systems and products cause additional work and expenses. All these reasons may result in higher costs for maintaining the plants.

Scalable DCS as an alternative to PLCs

Compared to PLCs, DCS for process industries are primarily based on control loops with slow monitoring- and control functions but less on fast positioning or switching operations. The process is usually operated and monitored in the control room. The systems and plants generally run continuously and often have very high demands when it comes to availability. Therefore, applying changes must be possible in online project configuration. Additionally, repairing and changing of components while operating the plant is an essential feature. Applications are often specifically configured for one project or process concerned and therefore require powerful and efficient engineering tools.

Driven by technological developments in the recent years, manufacturers of process automation technology are now able to offer control systems with higher scalability as an alternative to PLCs in process-oriented applications.  One of those companies is ABB with the Freelance DCS.

The advantages for scalable DCS are obvious: efficient engineering, easy operating and maintaining as well as increased productivity.

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Scalable system architecture

As regards system architecture, there are the following key components making up a Freelance DCS:

  • Freelance Engineering (Control Builder F)
  • Freelance Operations (DigiVis)
  • Controllers (AC 700F/800F/900F) and
  • I/O (S700/S800/S900).

Freelance can go from a typical OEM offering with an AC 700F controller, a Panel 800 and around 50-100 I/Os. The AC 700F can have up to eight direct I/O modules connected to it or have remote I/Os  connected via PROFIBUS. Modbus RTU and TCP are also supported. The Freelance Lite offering can typically have an AC 700F or AC 900F controller and will be in the 250 to 400 I/O range with possibly one combined Engineering / Operator station and a few operator stations. This can ramp up to the Freelance Standard and Premium offerings with the AC 800F and/or AC 900F, with or without redundancy. Freelance can go up to thousands of I/Os. Connections include Foundation Fieldbus, PROFIBUS and HART as well. There is also the possibility to connect to supervisory operator stations running on ABB’s System 800xA.

Take advantage from integration

The most apparent update in the latest Freelance version 2013 is the AC 900F controller. This extends the hardware portfolio of the process control system with numerous options, is twice as powerful as an AC 800F controller and yet fully compatible.

With Freelance, the advantages of a control system can now be used in automation solutions where previously PLCs were used – especially in process industries. In contrast to a PLC, Freelance offers all the advantages of a compact control system: a single engineering tool for all tasks. Freelance Engineering is used for configuration of the automation functions, the operator interface with displays and logs and fieldbus parameters of intelligent instruments.

Byworth Boilers, Keighley, UK, manufactures industrial boilers which include steam boilers, hot water boilers and accessories.
Byworth selected ABB’s Freelance to be at the core of the development of a new intelligent boiler house control system.

One of the main reasons was that Freelance has all the benefits that DCS architecture delivers: a primary aspect of this architecture being the single, system wide, global database for control and graphical display, which simply makes development much more efficient than fragmented PLC / SCADA solutions.

Convertors to extract platinum from ore in a mine from Northam-Platinum in South-Africa are driven using electrical motors.
Northam decided to use the small and somehow PLC-like AC 700F controller when re-equipping the control for the converters.

Before, a PLC regulated the motors' direct motor starters. The equipment had to be modernized and turn to frequency converters to increase energy efficiency and the outdated PLCs were to be replaced. The customer called for a more compact controller, improved presentation of alarms and results and an excellent cost/benefits ratio. That’s were Freelance with AC 700F came into play.

Saperatec GmbH is a technology leader in separating laminated structures and recycling the valuable raw materials obtained.
For Saperatec, the option to connect I/Os directly to the CPU was decisive. This simplified setting up the control system.

Due to the increased performance of AC 900F, the Freelance system also has power reserves for the future, which is an advantage for a pilot plant like this. These advantages include, for example, the use of a single engineering tool, the consistent, system-wide plausibility check of the user programs across all process- and operator stations and the graphical configuration with powerful editors.

Freelance can be used in various industries. Read more Freelance case studies by industry

Efficiency is essential

The Freelance Engineering tool (Control Builder F) allows easy, clearly structured and intuitive configuration of the native Freelance Operator Stations (DigiVis). Pre-engineered visualization components such as faceplates, module diagnosis, extended troubleshooting capabilities, ready-made system communication, event list, alarm line, trend displays with historian or automatically generated SFC displays. A comprehensive function block library with more than 250 industry proven and tested functions including faceplates saves extensive programming and testing effort.

Freelance Engineering verifies automation functions during configuration, and the application programs are formally checked for completeness and consistency, so errors can be found and removed quickly and easily. It also offers convenient cross-reference function allowing variables to be found easily in any editor right up to the graphic display. All these features improve transparency, readability and adaptability of the application and substantially increase the operational security. The whole control application spanning several controllers, including all operator graphics and all field device parameters are stored by the engineering tool in just one file. This complete project file is small enough to fit on small memory stick or even small enough to be sent via e-mail. The increased diagnostic analyses and improved alarm handling in the operation and maintenance phase allow costs to be cut and availability to be increased. This substantially increases the economic efficiency of the entire plant.

On the right track

It terms of distributed control systems, ABB has two offerings,” explains Elmar Vogt. “These are categorized as “Essential Automation” and “Extended Automation.”

The Extended Automation System 800xA was launched about ten years ago and is well introduced to the market. It is ABB’s solution for “extended” process applications, mainly for large-scale plants focusing on operator effectiveness and featuring high level of integration of control, safety, asset and information management, as well as electrical equipment.

Whereas Essential Automation downsizes the complexity. Along with the Freelance DCS, the Essential Automation offering also includes the Compact Product Suite, a set of Process automation products such as process controllers, safety controllers, field interfaces, process recorders and HMIs. These products can be used in combination or standalone.

There are two customer types: value-centric and control-centric. Each of them has specific characteristics. ABB’s value-centric customers for example have large engineering and maintenance department and are also willing to pay for a premium system, which also considers optimized strategies for the entire enterprise.

In terms of sales channel, the relationship is mostly directly with ABB,” explains Elmar Vogt. “System 800xA is ideal for this type of customer, for example a large oil & gas company”.

However, the control-centric customers feature characteristics such as being price-sensitive, preferring an easy-to-use system rather than a comprehensive, integrated client/server solution. He often doesn’t have huge engineering and maintenance resources available. The project sponsor more likely comes from engineering or plant operations than from executive management. Very often, system integrators act as the sales channel. Hence, ABB’s Essential Automation offering perfectly fits for control-centric users.

Typically, a systems integrator acts as the sales channel, rather than ABB. “Accordingly, our Essential Automation offerings are the right fit for the Control Centric customer,” notes Elmar Vogt. “There are training classes at ABB Universities, but we also provide self-learning tutorial to get a quick and easy start into the system.”

Meanwhile, through the range of available controllers, the system gives customers a very useful degree of scalability.

Elmar Vogt, global product line manager for Freelance at ABB Control Technologies:
“There are many plants that have decided to use PLCs but are actually a better fit for a DCS solution.”

Some of them assumed that a DCS is too large, complex end expensive requiring extensive engineering. For that reason they preferred PLC applications. But the DCS can be competitive with PLCs because it is very intuitive to use, saves engineering expenses and is easy to maintain and upgrade.

Value for your money

The Freelance DCS has a small footprint. Means that the system software can run on any standard PC, and the expenditures regarding engineering, commissioning and maintenance are relatively low. “The latest version of Freelance comes with a number of new features.” Explains Elmar Vogt.

These features include enhancements in Freelance Engineering tool, such as an intuitive auto router in the function block diagram (FBD) editor, and the ability to open multiple editors simultaneously.

In 2011, Carolina Automation Systems (CAS) attended the ABB Automation and Power World conference in Orlando and learned about the Freelance DCS. They were so impressed by the Freelance demo and its ease of use that they recommended the system to their customer, Wake Stone Corporation, who were on the lookout for a modern yet compact DCS solution.

Wake Stone awarded the upgrade project to CAS with kick-off in June 2012. Using Freelance, CAS had a fully engineered system up and ready for implementation for Wake Stone Corporation by August 1st, 2012.

Carolina Automation Systems (CAS) had no DCS experience and it was the first time ever they have used Freelance. But they were able to deliver on the tough project schedule.
One of the key success factors were time savings by using the same engineering tool for HMI configuration, communications and control functionality.

A PLC / SCADA solution would have involved more engineering tools, more tags and would have taken much longer to design.

Still plenty of potential

Although Freelance has now been around for twenty years and has developed large user bases in the specialty chemical industries in Germany and China, it is probably one of ABB’s “hidden secrets”.

There was not so much promotion for this DCS. Mainly word-of-mouth recommendation was a big factor. Once customers used it, they liked its ease of use and robustness.

Especially with the new AC 900F controller, introduced in 2013, Freelance opens huge potential across the globe in many industries for applications that do not require extended capabilities of a DCS.

Minimum engineering – maximum automation. This slogan summarizes what Freelance stands for: A cost-effective solution for process automation, just at the right size, easy to install and maintain.

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