Efforts to simplify the implementation and operation of FOUNDATION Fieldbus-based digital controls systems in the process industries continue to show progress, with the FieldComm Group’s Working Group helping the technology reach several important milestones.
Initially launched in May 2013, the Fieldbus FOUNDATION (now FieldComm Group) Usability Initiative was intended to make the digital fieldbus automation experience easier than conventional analog control systems in every conceivable way, from device setup to device replacement and daily maintenance practices.
The goal was to listen to the industrial marketplace and provide a managed infrastructure for process automation that allows end users to focus on their processes and their plants, not the technology tying everything together behind the scenes.
What is “usability?”
In the technical world, usability problems require the engineer to take off his or her engineering hat and think more like a user. The term “usability” is sometimes reduced to "easy to use," but this over-simplifies the problem and provides little guidance. A more precise definition can be applied to understand user requirements, formulate usability goals, and decide on the best techniques for usability evaluations.
The international standard, ISO 9241-11, provides guidance on usability and defines it as:
“The extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use.”
Usability is about:
- Effectiveness – Can users complete tasks and achieve goals with the product (i.e., do what they want to do)?
- Efficiency – How much effort do users require doing this (often measured in time)?
- Satisfaction – What do users think about the products ease of use?
Usability is affected by:
- The users – Who is using the product (e.g., are they highly trained and experienced users, or novices)?
- Their goals – What are the users trying to do with the product (e.g., does it support what they want to do with it)?
- The usage situation – Where and how is the product being used?
When it comes to industrial control systems and instrumentation, usability is all about human Interaction. It addresses the user experience and making the user interface (UI) simple and intuitive.
For many automation stakeholders, the inherent change from analog to digital technology hasn’t been the problem; it’s that users don’t understand how to employ new digital networks. Some plant engineering departments maintain a “4-20 mA mindset” in their technology decisions and practices. Instrument technicians have been known to ask, “Why can’t a digital device simply have its wires landed, be calibrated, and then start working?” Indeed, the idea of a device “driver” to make a device talk to a host system was once foreign to plant workers.
Identifying the challenges
The FOUNDATION Fieldbus usability initiative was conceived as a way to make intelligent devices easier to deploy and operate than traditional 4-20 mA technology. It began with surveys of the global supplier and end users communities to determine their “pain points” in utilizing fieldbus, followed by the development of case studies to resolve their issues.
An important motivation for the usability initiative was opening the market to applications involving single-loop controllers, supervisory control and data acquisition (SCADA) systems, remote terminal units (RTUs) and other hosts requiring a simplified interface to FOUNDATION Fieldbus. Working groups sought a manageable integration approach enabling end users to get started with digital technology as an alternative to traditional I/O, then expand data utilization through asset management applications, and finally advance to even more beneficial functionality like control in the field. In this way, plants could take advantage of the core features of fieldbus without encountering unnecessary complexity or training requirements.
A particular area of concern for the usability initiative has been eliminating the need to employ Electronic Device Descriptions (EDDs) for basic process variable (PV) integration – a key consideration in a wide range of device replacement scenarios. The goal is PV device interchangeability, whereby end users can swap out different vendors’ products with different feature sets and still get the PV value with no engineering effort.
In many cases, plants faced with replacing fieldbus instruments want to install the identical device type and software revision, as well as maintain existing PVs, diagnostics, etc., as part of a seamless, automated process.
An overall priority for working group members has been replicating familiar 4-20 mA work practices in fieldbus installations. Most industrial facilities have three distinct roles involved with control systems and device networks: Operations, Engineering and Field Technicians. System engineers are tasked with configuring the function blocks used by operators, while field technicians are responsible for device set-up. Unlike traditional analog environments, these roles can overlap with fieldbus. True “plug and play” performance means eliminating the need for Device Description (DD) downloads from the control system, especially when replacing field instruments during off-hours or on weekends. Personnel should be able to set a few key parameters (e.g., device tags) on the replacement fieldbus device, attach it to the network, locate it automatically, and receive the PV. This requires a distributed set of network configuration rules allowing system and device configurations to be pre-set without the need for a full system download.
Undertaking the work
The comprehensive, standards-based usability project had four main starting objectives for its development work: Backwards Compatibility, DD Templates, Automated Device Replacement, and Standard Connection Points.
Backwards Compatibility – This “future-proofing” technique allows users to feel confident that in a replacement scenario of a field instrument with a different revision level, they will be able to maintain a minimum level of functionality within the new device. While the user may not be able to take advantage of the latest feature enhancements of the new device, the backwards compatibility parameter will make it possible to operate the new instrument on the old device’s DD until the system can be updated with the latest DD file to take full advantage of the new instrument’s capabilities/enhancements. Backwards compatibility is an important part of developing full device replacement strategies in the future.
DD Templates – Further to the simplification of FOUNDATION Fieldbus, DD templates help users configure their devices to their specific application using a pre-defined set of values that come loaded in the device from the manufacturer. FOUNDATION fieldbus also allows for multiple templates to be supported in each device, thus giving the user additional flexibility to choose between varying templates. Each template in FOUNDATION fieldbus is identified by a label and can be filtered. Additionally, each template can contain local help information within the device.
The goal of DD templates is to give individual users a basic foundation upon which to build a specific device configuration. From there, the user can decide if it is necessary to make additional configuration changes or if the standard template achieves all that is required for the application.
Automated Device Replacement – Automation of device replacement allows the configuration in an existing field device to be restored in a newer version of that instrument without manual intervention. This “plug-and-play” solution ensures features are consistent between different generations of devices without reengineering the host configuration or changing any element of the H1 network other than the new instrument. This results in greater predictability in fieldbus implementation, while reducing integration risks.
Standard Connection Points – Standard connection points is the dream scenario for the “Saturday 3 a.m.” instrument failure that inevitably occurs during a blizzard. A user needs to quickly get the process back up and running with as little effort as possible. If he or she can at least get the primary value out of the instrument, then it’s possible to run the process until Monday morning when the engineering department shows up and can configure all the enhanced features like advanced diagnostics, control in the field, etc. Essentially, a user should be able to get the PV without a DD. By decoupling the PV from the DD, FOUNDATION fieldbus maintains all the benefits of advanced capabilities while gaining the simplicity of traditional 4-20 mA signals. In fact, FOUNDATION Fieldbus will be easier than 4-20 mA because devices will not need to be ranged or calibrated before the operator has meaningful data. It is the best of both technologies wrapped into a single architecture.
In 2014, the FOUNDATION Fieldbus specification was updated to include support for fieldbus device replacement and backwards compatibility, DD templates, field diagnostics and alarm/alert integration. The ability to utilize these enhanced features was included in Host Profile C, which required hosts to integrate field diagnostics into alarm management systems, rather than just provide access to the information in a device view. Application time support also became mandatory under Host Profile C. This feature requires a time stamp capability in the host system, which will start on an actual calendar date and time.
Status of ongoing efforts
FieldComm Group technical teams are currently validating new “fieldbus for I/O” specifications and working on device/system interface prototypes based on the usability initiatives. This will be followed by the release of Interoperability Test Kit (ITK) Version 7.0 incorporating developments such as standard connection points and other enhanced features.
FieldComm Group’s director-fieldbus products, Stephen Mitschke, stated, "The enhanced usability features in our technical specification will make it easier for both automation suppliers and end users to realize the full value of FOUNDATION technology. They are specifically aimed at simplifying fieldbus implementation, operation and maintenance.”
According to Mitschke, progress in the area of usability will eliminate arguments for the continued use of 4-20 mA technology in most process plants. End users will come to realize that FOUNDATION Fieldbus delivers the information they are accustomed to – in the same familiar format – while providing the opportunity to put advanced digital functionality to work when the time is right.
“Specifications and test equipment for backwards compatibility and like-device replacement are available today. Other valuable features, including DD templates and PV interchangeability, will be completed in the near future,” Mitschke said. “These system-focused solutions will provide an excellent return on investment and help industrial organizations take advantage of the inherent robustness of FOUNDATION technology.”
In conjunction with the usability initiative, FieldComm Group now offers a choice of test tools to meet the needs of the automation developer community. These kits are available at different levels, depending upon the technology features that must to be supported. For example, the latest version of the H1 ITK includes enhancements that make it easier for end users to replace “Like for Like” devices. In other words, the procedure for replacing a device with a newer revision level of the same make and model of device is automated to allow the configuration in an existing field instrument to be restored in a newer version of that instrument without manual intervention.
Currently available test kits include:
- Host Test Kit 2.0.1 – Includes Profile C and FDI testing
- DD Services / FF DD-IDE – Includes maintenance updates
Planned 2017 releases include:
- Standard DD Library Updates – SCP and maintenance updates
- ITK 6.3.0 – Standard Connection Points (optional)
- Host Test Kit – Supporting Standard Connection Points
- H1 ITK 7.0.0 – Standard Connection Points (mandatory)
Long-term releases include:
- Host Test Kit – Update with common Field Device Integration (FDI) UI test cases
- Automated Physical Layer Testing
Looking to the future
FieldComm Group will continue this Usability Initiative to encompass all of its technologies to drive an innovation strategy enabling plant owners to focus more on what technology can do for them and their business, versus how they manage the technology itself.
Focusing on standards-based solutions will make it easier for automation suppliers to develop new fieldbus-based products and applications. In addition, FieldComm Group’s testing and registration process is designed to ensure registered FOUNDATION Fieldbus devices, systems and components all work together as they should.
In the future, FOUNDATION Fieldbus will be more effective, efficient and user-friendly than ever before!
For more information, please visit the FieldComm Group website.