Stephen Mitschke
August 12th, 2003, 01:38 PM
Dear All,This thread has turned into a separate discussion on what is missing in DD.Not much is missing in the latest versions of DD/CFF. The files aresufficient to make all device- and control strategy configuration and allbut the most advanced device diagnostics. DD was originally conceived forHART quite some time ago. Over the years devices have become more advanced,capable of performing sophisticated diagnostics that cannot be presented asa simple text message. For example, valve performance assessment andwear-and-tear history requires charts and graphs to be illustrated in acomprehensible way. Diagnostics itself is often proprietary methods but theresults must be possible to display in an open way. Therefore a technologyis necessary to make it possible for device manufacturers to design pagesfor powerful diagnostics and analysis. To configure and checkout devices thethree standard files is all you need. Indeed, for many devices in theforeseeable future DD/CFF may be all you will need. A notable exception thatappeared on this list last December is valve positioners. To make the fancycharts and graphs for valve signature, hysteresis and step-response the DD(at least in its current form) is not enough.To enable also graphical analysis and some other stuff an add-on isrequired. Something must be added for this enhanced functionality to bedisplayed in an open way. We (Smar) as a host supplier decided to leave ourconfiguration tool (Syscon) "as-is" using only standard files. For the newasset management software we took the step to add new technology, which hasas little "proprietary" content as possible. It was not an easy decision butusers want this graphics today, and not only for "live" data, but alsohistorical records. Asset management software must not restrict fieldinstrument selection as outlined in the NAMUR NE-91 recommendation. In spiteof a new technology it must be possible to include third-party devices withminimum effort.One supplier when designing a user interface cannot give full justice to adevice from another supplier because the device capability is not fullyunderstood. We want to give the instrument manufacturers the opportunity tointegrate their devices themselves with full scope of functions. I.e. amodel where Smar, but also device manufacturers (and even end-users shouldthey have to) can design device pages similar to laying out HMI graphicstoday. No one technology does this, so an aggregate of technologies isrequired for this model. For the presentation tier we selected an existingtechnology that is common, open, widely accepted and well understood. Wewanted a technology others also can dominate, empowering them to developdevice pages. The technology meeting these criteria is called ASP, ActiveService Page. This is an existing web technology that you are in touch withevery day without even thinking about it. The device manufacturers know bestwhat information to display, and how to present it for the user to get thebest out of their device. The device manufacturer is the ideal candidate tomake pages available for their devices and keeping them up to date with thelatest features and capabilities. This model is completed by OPC and ADO atthe data tier. The pages are viewed using a standard web browser andincludes live as well as historical data. Maybe this model, or a derivative,can supplement where needed DD.Anyway, it may be a good idea to look for a host that can fully configuredevice and control strategy, perform calibration and show text-baseddiagnostic error messages using only the three standard device support filesbut as an option use additional files e.g. for asset management.Jonas BergeSmar Singapore