June 15, 2006 by Ian Verhappen
The “smart” field devices being installed in todayÃs facilities, including the various fieldbus and HART-enabled devices, are designed to improve maintenance practices, resulting in a 40 per cent savings of total operating costs. The trick, of course, is getting the data from the devices to the maintenance planning tools where it can be used.
This is a challenge because, despite the fact that each field communications protocol is based on a standard, no open standard yet exists to fully define how the maintenance data is to be stored and presented between the field devices and control system, and then again between the control system and the maintenance system.
At present, each asset management solution is vendor proprietary and requires “mapping” or special software drivers to access the data from the field. In legacy systems, the problem is further compounded because the asset management solution is not able to be an integrated part of the control system, and must be installed in parallel, requiring an extra pair of terminations to a multiplexed signal modem.
Fortunately, data in most asset management systems can easily integrate with the associated control systems, so that key parameters related to device health and status can be made accessible to the process operators to control problems and optimize plant operations.
The additional good news is that progress is being made on better defining a minimal set of parameters for each type of field device. These parameters must be included with every device as part of the certification process. These transducer block/device profile standards will define the maintenance, diagnostic and calibration information required for different groups of devices (eg. temperature transmitters, pressure transmitters, rotary valves and linear valves). In addition, the enhanced electronic device description language (EDDL) and FDT/DTM standards are defining how devices will look on host systems, making it easier to transfer data from the host to the asset system, in effect transmitting the data in reverse.
With the data now in the asset management system, the next step is to get it into the corporate business system, including the maintenance and inventory planning tools. Once again, we face a standards dilemma, in which there is no solution yet in place.
The good news, however, is that multiple parallel activities are underway that will hopefully present a solution in the near future. The bad news is that this could result in too many competing solutions.
The following are among the possible solutions for business integration standards:
• ISA-20/Prolist–This group is working on an IEC standard (IEC 65B Working Group 11) to create a life cycle device profile (specify, purchase, operate, decommission) based on objects using the XML language. Protypes are already being tested in Germany.
• ISA-88/95 and OAGIS – Building on the existing ISA standards to integrate control and business systems, this group is working to define the data structures for integration from field to business systems.
• MIMOSA – A group working on defining data structures for complete facilities with automation.
Of course, making all of this come to fruition requires significant effort by many volunteers. If you feel that these activities are important to your organization, especially if you are an end-user, I encourage you to become involved in one or more of these working groups. Remember, now is the time to make a difference. It is much more difficult to change something after it has been adopted and implemented than during its creation.
I hope you join me and many other volunteers in becoming part of the solution. See you at a standards meeting soon!
If you have any suggestions for topics that you would like to see covered in this column, please send me a note and I will try to include it in the future as it fits with the editorial calendar.
- At the Hannover Fair in April, the SERCOS Trade Organizations announced the release of the specification for the Controller-to-Controller (C2C) Synchronization and Communication Profile, a profile for interconnecting motion controllers using the new SERCOS III industrial Ethernet-based standard for motion control. This effort addresses the increasing need in manufacturing systems engineering in which individual machine modules not only need to be connected mechanically, but also need to be integrated into communication networks and coupled in real-time.
- The OMAC Packaging Workgroup (OPW) approved the PackAL guidelines at their March meeting in Orlando, Fla. PackAL is an application library of common software elements used in packaging applications that was developed by the PackSoft subgroup of the OPW. The application library is made up of 23 functions Ã³ 13 are machine functions, such as wind/unwind, dancer control, registration and indexing; nine are communication functions for horizontal line communications; and one is for the PackML machine state model.
- The Fieldbus Foundation has released ITK Test Kit version 5.0 to fully test and support the new functionality of the Phase 1 enhancements made to the Electronic Device Description Language (EDDL).
Ian Verhappen, P.Eng. is an ISA Fellow and director of ICE-Pros, Inc., an independent instrument and control engineering consulting and training firm specializing in fieldbus, process analyzer systems and oil sands instrumentation and control. E-mail him at Ian.Verhappen@ICE-Pros.com, or visit www.ICE-Pros.com.