Commission and Diagnose a Device Communication Problem from the Comfort of the Control Room?

FDT Can Reduce the Start-Up Node Commission Time by Up to 80%

By Kristen Barbour

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Fieldbus has proven its value in practice. Fieldbus communications are stable, and users enjoy smart digital communication all the way to the field device, enabling many new opportunities for increased plant availability, faster start-up and plant asset management (PAM). Any experienced users would agree: Good installation practices are the most significant influence on the quality of long-term communications. A well-executed installation is invaluable in protecting plant operations. Determining a solid installation has traditionally required a high degree of technical knowledge and sophisticated electronic equipment. Loop check procedures, including checking cable continuity, testing resistance and capacitance, analyzing signal level and noise, etc., were time-consuming and labor-intensive manual endeavors. FDT has changed all that and can reduce the start-up node commission time by up to 80% when compared with traditional analog installations.

Advanced physical layer diagnostics (APLD) is more than just a tool to alert you of communication problems. APLD tools have the ability to take device commissioning and segment verification from days to a few hours. DTMs are at the core of APLD, and the user-friendly interface brings all the diagnostic information into the asset management systems. These tools have features such as the DTM fieldbus oscilloscope with fieldbus-specific triggers to capture intermittent communications to evaluate digital communications for field devices. This accessibility helps identify communication issues and warnings long before a device fails by identifying components that begin to negatively affect bus communications. These are important functions for operating efficiency and adopting condition-based maintenance strategies.

Why Do You Need APLD?

Over time, any number of negative factors can compound and degrade communications, resulting in network instabilities and unplanned shutdowns. To keep your facility proactive to minimize problems in the field, having a healthy physical layer to transmit this information is critical. When changes in the physical layer are reported, maintenance technicians can check those devices that have issued a warning of a potential problem and decide on corrective action before any potential failure occurs.

Fieldbus diagnostic tools with online monitoring capabilities, such as the FieldConnex Advanced Diagnostic Module (ADM) from Pepperl+Fuchs, monitor everything from load conditions to noise, to ground faults, and measure the device signal level. Status information is easily communicated to the DCS.

How Does It Work?

The ADM provides an easy to use diagnostic software tool, a DTM that can be used in any FDT/DTM frame. Think of this as a "fieldbus specialist" in a box! All the knowledge resides in the ADM and is easily interpreted using the DTM. When a fault or shift in communications happens, the ADM interprets physical layer data and translates measurements into actionable information. Physical layer monitoring tools like the Pepperl+Fuchs' ADM takes the guess work out of fieldbus and provides value to the user in every stage of the fieldbus project:

  • Commissioning, including documentation
  • Operation
  • Troubleshooting

The ADM enables proactive plant management and plant upkeep. With the ADM, the fieldbus physical layer becomes an asset that is measurable. It can be integrated into plant asset management systems. The Diagnostic Manager creates a visual representation of the digital fieldbus communications. The ADM provides the "extra set of eyes" on the communications making users aware when needed that a problem is about to arise. In conjunction with the ADM, the Diagnostic Manager makes working with fieldbus easy.

The Diagnostic Manager…

  • eliminates time-consuming, repetitive and labor- intensive steps during commissioning,
  • provides detailed analysis of each segment,
  • evaluates each segment for conformity to fieldbus specifications and monitors each connected node on the segment.

The commissioning wizard leads the user step-by-step through a complete system and segment check-out. During this procedure, all necessary individual system and segment data of the installation are determined. The commissioning wizard proposes limit values for all system and physical layer values by segment and by node. Each segment is documented with maintenance required limits in its best possible state.

A real-time fieldbus oscilloscope shows the actual waveform of the fieldbus signal and can be triggered on numerous fieldbus related events, such as telegram types even from a particular node or address.

The oscilloscope can:

  • trigger on message "Out of specification,"
  • take and store up to 10 recordings in a row,
  • identify telegrams by sender, telegram type,
  • indicate each bit in the telegram.

It enables a fieldbus expert to pinpoint the otherwise hard to track problems. Behavior caused by compound errors or errors that occur sporadically can be analyzed.

Physical-layer equipment with FDT technology provides leading-edge diagnostics that measure and maintain reliable fieldbus communication. Plant operations are not adversely affected by maintenance work, water ingress, loose wire strands or corrosion. Over time these negative factors compound and will degrade communication signals leading to network instabilities. Real-time monitoring of the physical layer provides early notification of changes before they have a negative effect on the fieldbus signal.


ADM for FDT Group

Fieldbus has proven its value in practice. Fieldbus communications are stable and users enjoy smart digital communication all the way to the field device, enabling many new opportunities for increased plant availability, faster start-up and Plant Asset Management (PAM). Any experienced users would agree: Good installation practices are the most significant influence on the quality of long term communications. A well-executed installation is invaluable in protecting plant operations. Determining a solid installation has traditionally required a high degree of technical knowledge and sophisticated electronic equipment. Loop check procedures, including checking cable continuity, testing resistance and capacitance, analyzing signal level and noise, etc., were time-consuming and labor-intensive manual endeavors. FDT has changed all that, and can reduce the start-up node commission time by up to 80% when compared with traditional analog installations. View this video to learn how.

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