FOUNDATION Fieldbus: the Diagnostics Difference
There s Diagnostics and There s Diagnostics. The Value of Fieldbus Diagnostics Physical Layer Diagnostics Managing the Diagnostics Storm PAM and IDM Software, Work Processes and Training
Why do we Use Diagnostics? Diagnostics can be a valuable tool that can help save you time and money and avoid unplanned shutdowns. Diagnostic data can be vague and require a lot of digging to get to the root cause. Diagnostic data can also provide you with avalanche of useless information that can grind your process to a halt. Not all technologies handle diagnostic information the same way. Trick is to get only the right information, at the right time, to the right people.
The Current State of Non Digital Diagnostics: Or the Idiot Light Doesn t tell you what s wrong No predictive guidance Is it a process problem or device problem? Sensor problem? Electronics problem? Who knows.
The FOUNDATION Fieldbus Diagnostics Difference FOUNDATION fieldbus has a unique approach to management of device diagnostics. The publish/subscribe structure of FOUNDATION fieldbus means that diagnostic information is available immediately to a wide range of workers in the plant. Data is available at all times and is constantly being updated. Allows you to organize and prioritize data in a way that turns it into useful information for the right people at the right time.
Fieldbus Device Alerts Bring the Data to the Front Early warning system Gives operators more time to take action before device problem affects the process Time-stamped Sequence of event recording Relate problem time to true causative factors
Actionable Information In the past, device alarms were not displayed with actionable information Just error messages or cryptic codes Error 13 The technician didn t know what to do Device alarms must be displayed with advice that maintenance technicians can act upon Use devices which provide guidance for the device diagnostic alarms... Understandable Diagnostic Advisory Focusing Provide a clear message that is easily understood, not a cryptic code Helps with the identification of the problem Provides guidance towards the correct action Directs attention to the important aspects
Distinctions should be made between Instrument and Process Diagnostics Root Root Instrument Instrument Information Information Group Group Sensor Sensor including process connection and sensor electronic Electronic Electronics Configuration e.g. Linearization Process/ Process/ Environment Environment Process Process
Data Quality Indication in Action
Device Problem or Process Problem Do you have sufficient data to guide you? Hardwired Device drives current <4 ma or >20 ma on device failure Masquerades as a process problem PID counteracts thus tripping the loop Operator cannot tell the difference between a process alarm and a device alarm Fieldbus Device health indicated by associated status Clear distinction between device problem and process problem Controller holds last position and alarms on device failure Shutdown is optional Operator can easily distinguish process problem from a device problem
After the Fix Embedded Causes? When was device configuration changed? Who did it? What was changed?
Fieldbus Pressure Transmitter Data Provides: More versatile statistical process monitoring Uses process noise to detect process problems: Pulsation indicative of pump or compressor damage Entrained air = flow measurement errors Leaks in impulse lines and manifolds Plugged impulse line
Fieldbus Temperature Transmitter Data Provides: Statistical process monitoring: Hydrate formation, scaling formation, thermowell coating, etc. Predictive thermocouple degradation diagnostics - before a T/C or RTD fails, Extreme Temperature Tracking Heat conducted from integral sensor to transmitter housing
Fieldbus Control Valve Positioner Data Provides: Continuous (not on-demand) Performance Diagnostics: Actuator/tubing leakage, air supply availability, calibration shift, etc. Common Diagnostics Partial Stroke Testing (PST), travel histogram, step-response, valve signature, pressure sensor failure, travel deviation, reversal count alert, accumulated travel alert, supply pressure, position feedback
Fieldbus On/Off Valve Data Provides: Open/close travel time On/Off Valve Cycle counts Stuck valve
Fieldbus Data Goes Beyond Common Transmitters and Valves Tank Gauging Systems Gas Chromatographs
Segment data can provide a good analysis of the system s health and may include: Monitoring and diagnostics Online and in real-time with remote access Simple-to-interpret data reports Built-in oscilloscope for visual detail Communications Data - Testers/Communicators
Data can Appear in a Variety of Forms Diagnostic Lamps Diagnostic Windows
OK, so FOUNDATION Fieldbus clearly can provide the data I have always wanted So what can possibly stop me from getting the most value from the data?...
The Power is in the Data, and there can be a lot of data! Different Manufactures = different levels of granularity (data) Manufacturer (Coded) Block Type A B C D E F G H I J K L Number of Parameters in each block XD 1 (generally the measurement transducer) 44 106 85 34 37 91 45 29 45 61 45 42 XD 2 38 42 36 50 34 27 XD 3 93 20 XD 4 55 17 XD 5 33 # of parameters 230 148 121 34 37 211 45 29 79 88 45 42 # of Transducer Block Parameters in d/p transmitters. Extracted from Differential Pressure Transmitters with similar capsule ranges At least one device contained~75 parameters specifically for specialized diagnostics
The Diagnostics Storm Sample Diagnostic Parameters of a FOUNDATION Fieldbus Flowmeter
NAMUR NE 107 Definition of NE 107 Status Signals
Definition of NE 107 Status Signals
32 Bit Bitstring for Prioritizing Diagnostic Data
Grouping Diagnostic Conditions
Diagnostic Mapping Workflow
Embedded in Supplier Solution
Utilizing Diagnostic Data from Multiple Devices Together Certain diagnostic anomalies expressed in multiple field devices can indicate an anomaly or impending abnormal situation in the process. Placing a structure around which these diagnostics can be consistently managed makes these more advanced diagnostics possible. Being able to diagnose the overall health of a unit, area, or even the entire plant is predicated on this good diagnostic data at the most basic level of the measurement devices and actuators.
Plans for Using a Plant Asset Management System
Location of Intelligent Device Management Software In the past, intelligent device management software fell into disuse because it was not easily accessible Hidden away in the workshop Local equipment room (LER) / field auxiliary room (FAR) Stand-alone workstation in the corner of the control room Separate login Must type the tag to search Must be accessible to become a natural part of the daily work process Client integrated on the operator console A mindset change The idea is not for operators to take over maintenance Dedicated maintenance workstation for instrument technicians
Operators Using Device Diagnostics as Early Warning for Process Intelligent device management client integrated in DCS operator console Device diagnostics becomes a natural part of daily operations Operators tend to the process, not the devices Plus: Device Configuration Traditional Plus: Architecture Device Diagnostics Plus: Process visibility Engineering Operator Operator Operator Maintenance
Training for New Competency In the past the operators got training on the operator station software But not the device management software The technicians got training on the handheld field communicator But not the device management software Make sure operators and technicians are trained on the device management software Understand the NE107 status signals Navigate the device menu How to search for tags, plant unit, device classes How to search for specific device types
Work Processes Have to Be Rewritten Around Device Management Software Standard company work processes for 4-20 ma and on/off signals are not optimized for intelligent devices Technicians start by going to the field to inspect Rewrite work processes around the device management software Urgent maintenance: Troubleshoot and verify from the device management software first, before going to the field, to determine if there is a problem Daily maintenance: Extract device diagnostic alarm report from intelligent device management software, and prioritize before morning meeting Turnaround maintenance: Screen which devices need calibration and adjustment to better plan the turnaround activities
Let s Now See Device Diagnostics in Action!