Three wishes for an easier life with HART
Pelz believes that HART Communication is a very useful technology for plants, which incorporate a mix of old and new devices, some of which use only 4-20 mA. "HART makes integrating new devices into our legacy system a problem-free task," he said.
"With central device management tools it is possible for us to configure all our HART devices in the plant from a central position, in the control room, which saves us a great deal of technician time. From a single engineering tool it should be possible to work with all the devices and this is the way we want to go," continued Pelz.
"The use of WirelessHART allows us to monitor devices in areas of the plant that would be too costly to achieve using wired devices, helping us achieve our goal of continuously improving plant productivity." Pelz also explained that the plant has a lot of moveable assets, and that WirelessHART technology also makes these devices much easier to handle.
Pelz concluded by calling on device vendors to make life easier for end users of HART devices such as himself in three particular areas. Simplified and unified device integration software; reduced device complexity for basic functionality; and simplified device diagnostics capabilities, in line with NAMUR NE 107. He said: "I feel that there are too many different device integration software tools. It would greatly minimize our device integration efforts if we had just one, universal device integration tool for all of our HART devices." For this reason he supports the replacement of existing device integration methods with FDI which will standardize all of these methods.
On the subject of device complexity Pelz said that the increasing functionality being built into devices makes them much more complex. "If I need the same information from three different devices from three different vendors, I will need to look in three different places!" he said. "Life would be easier if HART device vendors were to place all the basic functionality, in the same place and maybe bury all the vendor specific functionality a little deeper into the device."
Finally, Pelz called for the universal implementation of NAMUR NE 107 guidelines, which relate to self-monitoring and standardized condensed device diagnosis of field devices, with a series of recommendations on how to present diagnostic data and reduce the number of diagnostic indications from a field device to just a few symbols. These comments confirm that HART technology provides significant value to users by providing device and process information that improves plant productivity and users like Mr. Pelz views intelligent HART-enabled devices as a key asset in their operations.
HART device vendors have responded to these requests in different ways. John Yingst, product manager at Honeywell, believes that device vendors will always want to differentiate themselves from the competition by offering additional capabilities, which is directly opposed to end-users requests for greater standardisation and simplicity. However, he says that there are a few developments that could help the end user.
Yingst explained: "Firstly, without making changes to the devices themselves, more vendors are embracing FDT/DTM technology as a way to create their own unique user-friendly interfaces for both maintenance and engineering users. A DTM looks the same in any ‘frame’ or system it is used in which helps the maintenance guy who might have more than one control system in his plant. However, the user has to learn each vendor’s look and feel and I do not see this situation changing.
"Although HART now follows NAMUR NE 107 guidelines, there are still a great deal of devices in the field already in use which do not," continued Yingst. Honeywell can offer a number of system features and capabilities to help with this problem. Experion Station has the ability to direct device alarms away from the operator console, for example. On the device side, Honeywell uses HART capabilities to display messages from the control room on its SmartLine transmitter graphic display. "This helps field operators better identify and diagnose device maintenance. And, we are complying with NAMUR 107 guidelines," said Yingst.
Kurt Polzer, business development Wireless Products for Process Automation at Siemens responded as follows: "Siemens supports both EDD/EDDL (Electronic Device Description Language)-based solutions and DTMs-based tools approaches, with a focus on EDD/EDDL technology, because our standard tool Simatic PDM is based on EDDL. To enable the user to operate our devices in an FDT-based tool we have the Sitrans DTM which is a single DTM that manages most of our devices just by using EDDs. However, we always strive to make things easier for our customers and have supported the Field Device Integration (FDI) initiative from the outset."
Further steps being taken by the company to offer easier integration and improved diagnostic capabilities include the introduction of Sitrans Library which offers easy integration of Siemens field devices into its Simatic PCS 7 process control system and the Simatic automation environment. "Because the integration of all field devices into control systems is standardized – with identical function blocks to build up the control strategy and identical faceplates in the HMI for the operator – additional features which are not supported by the standard are not displayed in the faceplates. Such features and the information provided by them are known as being "stranded in the field." Users of Sitrans Library have full access to all device features, and faceplates will include both a direct view of all information, diagnostics and events and direct access to all relevant functions," said Polzer. "Once initial devices have been added to the Sitrans Library, we will integrate further devices."
Adherence to NAMUR NE 107
Frank Fengler, head of device integration management at ABB Automation Products GmbH, stated that ABB already adheres to NAMUR NE 107 requirements. "We started this process with the integration of asset management into our systems," he said. The company’s Asset Optimiser tool, for example, includes an Asset Monitor application that shows all the diagnostics information of devices in accordance with the NAMUR guidelines. "In addition, this provides a description, possible cause and suggested actions for each message displayed. Asset monitor is a vendor independent tool that works with all DTM or EDD-enabled devices."
On the subject of device integration software tools, Fengler explained that today ABB has a single integration tool and in the future will also offer an FDI-based solution. "The devices themselves will not change, but will simply be given an additional ‘file’ in the driver," said Fengler.
Finally, Fengler mentioned some ABB moves towards reduced device complexity. He said: "ABB can offer its Asset Vision Basics tool as an application with a easy-to-use graphic interface that connects directly to a device and brings up the screen needed to configure the most important functions of the device. Further, the ABB pressure transmitter range features a single device file so it is not necessary to search for the correct device driver software for a particular pressure application."
Bob Lattimer, senior principal engineer at Emerson Process Management said that Emerson fully supports the provision of NAMUR NE 107 in its devices. "We have not yet registered any devices, However, NE 107 functionality will be included in all new field devices in the near future – starting in 2014," he promised.
Emerson is also working hard to provide consistent integration across its product range and ensure that the behavior of its devices is consistent. "We are also working hard to ensure that the behavior of devices is also consistent. Standardization will certainly make life easier for the end user, if the devices all behave in, essentially, the same way. The introduction of FDI should remove the configuration inconsistencies that occur in all communication protocols today," continued Lattimer. "The primary goal for FDI is to ensure good consistency across all host vendors, for any given protocol and it should make device integration easier."
He concluded by saying: "Emerson recognizes diagnostics capabilities as a valuable feature for field devices and we are always innovating in this area, particularly around instrumentation. Delta V already includes NE 107 type functionality and our HART devices have had NE107 functionality for several years in the host system. The next step is to move this functionality down to the device to offer higher functioning systems, even when NE107 capability is not built into the host system."
Vendors will always want to make ‘individual’ products, but it would seem that recognition is now growing in the vendor community that the end-user customer wants their devices to be simpler. The introduction of standards appears to be helping, but this is a sensitive area for vendors who will always want to ‘innovate’ and differentiate themselves with ever more distinctive features and functions.
Regarding Mr. Pelz’s three wishes, it appears that there are options and solutions that are available today that address the simplified and unified device integration request. FDI will standardize and unify device and host integration and is supported by all of the major field communications organizations.
Regarding the challenge to have reduced device complexity for basic functions, in addition to what was mentioned above, HART has Universal and Common Practice Commands that provide the majority of the configuration parameters needed to commission a device. HART also defines device families (like pressure, temperature, level, etc.) that identify common parameters for devices and standardizes the basic functions for each different type of measurement reducing the complexity for the parameterization of basic functions.
Lastly, the simplified or standardized condensed device diagnostics as outlined in NE107 is currently available in several HART-enabled applications and more implementations are expected in the future. HART Communication is indeed making life easier!
Suzanne Gill is editor of Control Engineering Europe.
– See related articles below.