Three wishes for an easier life with HART
At Hannover Messe 2013, Michael Pelz, head of process optimization and automation for Clariant Pigments Business Unit, spoke about his experiences with HART technology, while expressing his hopes for future developments to make the technology even easier to work with.
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."