Communicating Diagnostics via EDDL

It’s often difficult to understand the value a new international standard brings to your process manufacturing operations. Emerson’s Jonas Berge has been hard at work in his capacity on the standards committee ISA104, Electronic Device Description Language (EDDL) to educate process automation professionals. In addition to the standards committee Jonas contributes his energy to the website and the EDDL email list. You can also see some of the other times I’ve featured his work.

His latest article, Temperature Transmitters: Warming Up to EDDL, in Industrial automation asia magazine, describes how enhancements to EDDL (a.k.a. IEC 61804-3) have improved setup and diagnostics of temperature transmitters.

Jonas describes how the technology in temperature transmitters has advanced to provide diagnosis of their health, the sensor wiring and the temperature-sensing element. This diagnostic information is communicated back to the asset management and/or automation system via digital protocols such as HART, WirelessHART and Foundation fieldbus.

An example Jonas offers is a temperature element burnout. The temperature device uses the EDDL standard to

…provide image displays, switched dynamically, that illustrate the problem.

Some of the more sophisticated temperature transmitters have dual sensing elements. Sensor drift can be determined and reported back to an operator or maintenance technician if a maximum difference is exceeded between the two measurements. These dual sensors can also operate in a hot-backup mode if they measure the same point. They are set in a primary/standby mode where failure of the primary sensor causes its value to be ignored and the backup sensor to be used.

Jonas also describes a loop-testing scenario typically performed by maintenance technicians:

Systems and software that fully implement IEC 61804-3 support EDDL wizards that take the technician through required steps to check the temperature transmitter as defined by its manufacturer.

The wizard reminds the technician to inform the operators that a loop test will be performed so the associated control loop can be changed to manual to prevent upsetting the process when temperature is simulated.

The EDDL standard provides a standard way for device manufacturers to embed help into these devices, which reduces learning hurdles for operators and maintenance techs to use these diagnostics.

Thanks to Rohit Kadam for pointing this story to me in his Nice To Meet You..! blog. Rohit is an active member in our DeltaV Twitter Community.

Posted Wednesday, July 2nd, 2008 under Interoperability, Measurement, Technologies.