Continuing along the theme of last month’s column, I’d like to carry on with the discussion about the importance of diagnostic information, and the integration of this information into asset management software. Unfortunately, far too many installations that have smart instruments such as HART are not taking advantage of this information, and are only using the digital capabilities of their devices to communicate with their handheld calibrators. Handheld units certainly make working on these instruments much easier; however, without the centralized database – typically asset management software – the real value of maintenance and diagnostic information cannot be realized.
At its most basic level, asset management software has the advantage of being able to aggregate information in a variety of ways. This ability makes it possible to see trends and common failures that will point to root causes of faults, so that the faults can be corrected rather than continually patched.
One challenge to the adoption of integrated asset management is the lack of standards at all levels of the integration – from field sensors through to ERP systems. Fortunately, progress is being made on developing such standards. However, it is not one standard; it’s a series of standards. The "trick" – or opportunity – for integrators will be defining the interfaces between the various systems at each of the ISA-95 levels of data storage/reporting. ISA-95 has defined a model that describes the type of operations at each level of an integrated manufacturing enterprise – from the sensors at Level 0, through to the business planning systems at Level 4.
Let’s take a look at what is happening in standards development at each of these levels. Starting at the base, Level 0/1, where the sensors for which we want to collect diagnostic information reside, we have HART and the various fieldbus protocols. Fortunately, HART, Foundation Fieldbus and Profibus PA are all based on EDDL technology and, as discussed earlier this year, these groups are working on the next generation of this technology – called FDI. FDI will define a common interface for these three protocols, so that the majority of process facilities will only have one type of interface between levels 1 and 2. In addition, the Fieldbus Foundation is developing a series of standards for the transducer blocks in which all of the maintenance and diagnostic information is contained, so that regardless of which manufacturer’s sensor is installed, it will be possible to integrate directly into any asset management software tool because all of the parameters will have the same name and information.
Level 2 is where the controllers reside. How many times have each of us operated our plant with "bad data?" Foundation Fieldbus technology makes sure that this does not happen by sending out a status message every update cycle. However, it is possible to get close to the same result using other digital protocols. All that is required is to read the status bit on a regular basis and incorporate this information into your control algorithm.
Level 3 is where most of the asset management software tools reside. Unfortunately, I am not aware of any standards being developed specifically for this level; hence, the reason for the integration challenge of connecting these tools with the ERP software used to manage the complete facility.
The ERP or business planning applications at Level 4 are being discussed by a number of groups, most notably the ISO PAS-55 standard, as well as the MIMOSA (www.mimosa.org) organization. MIMOSA is a not-for-profit trade association dedicated to developing and encouraging the adoption of open information standards for operations and maintenance in manufacturing, fleet and facility environments. MIMOSA’s open standards enable collaborative asset life cycle management in both commercial and military applications.
There are also a number of activities underway to help integrate all the levels through the complete life cycle of a device and system. Most notable among the life cycle standards work, from an instrumentation perspective, is the NAMUR (www.namur.de) activity under the auspices of Working Group 100, known as ProLIST. ProLIST is working on a plant life cycle management standard (actually, a series of databases) for the full range of field devices. These databases will track an instrument for both manufacturers and end users from the moment it is specified, through procurement, manufacturing, installation, maintenance, removal and disposal. Part of the incentive for this is to enable competitive bidding on every type of device, as well as quality tracking (because it is possible to trace every component back to its original source by the manufacturer). Another incentive is the ability to determine the environmental impact for any possible hazardous chemicals or materials in the device. This is obviously a huge effort, and will take many years to develop the standards and the associated databases and infrastructure to make this possible. The outputs of the ProLIST group are being incorporated into a series of IEC standards under the auspices of TC65E Working Group 2.
As you can see, information to better manage your field devices and your operations is available. The tools to do so are also moving towards a more open, more easily integrated option, which will hopefully make it easier for all of us to better use the tools and information we have to improve our overall maintenance operations.
Ian Verhappen, P.Eng., is an ISA Fellow and ISA Certified Automation Professional. He operates Industrial Automation Networks Inc., specializing in field-level industrial communications, process analytics and heavy oil/oil sands automation. He can be reached at firstname.lastname@example.org.