Troubleshooting

Course 1 – Troubleshooting Single Loop Control Systems

Prerequisites: This lesson is designed for participants familiar with test instruments and their functions within a control loop and fundamentals of process measurement. A knowledge of reading process control diagrams is also recommended.

Description: This lesson describes the systematic approach to troubleshooting and applies that approach to single loop control systems. The lesson explains and demonstrates troubleshooting steps such as verifying that a problem exists, identifying possible causes of the problem, dividing the system to isolate the cause, recommending corrective action, and following up to prevent future problems.

Objectives:

• Describe the purpose of troubleshooting process systems and identify the reasons a systematic troubleshooting approach is most effective
• Verify that a performance problem exists by gathering information from sources such as the operator, diagrams, trend graphs, historical data, and system performance
• Locate and identify the possible causes of a performance problem based on information gathered about the system in the quickest, most efficient way possible
• Divide the system to isolate possible causes
• Check each possible cause to determine if it is the source of the problem
• Identify and carry out or recommend appropriate corrective action once a performance problem has been located
• Verify that corrections have been made by consulting resources such as the operator and observation of system performance
• Take or recommend appropriate follow-up procedures to minimize the potential for recurrence
• Apply a systematic troubleshooting approach to its proper conclusion in single loop flow, temperature, level, and pressure control systems

Course 2 – Troubleshooting Multi-Loop Control Systems

Prerequisites: This lesson is designed for participants familiar with instruments and their functions within a control loop and how they are represented on process control diagrams. An understanding of a systematic approach to troubleshooting single loop control systems is also required.

Description: This lesson discusses the application of the steps for applying the systematic approach to troubleshooting multi-loop control systems. Emphasis is placed on isolating possible causes to the appropriate loop of a multi-loop control system. The lesson applies the basic troubleshooting procedure to ratio, cascade, and feedforward systems.

Objectives:

• Apply the systematic approach to troubleshooting malfunctioning multi-loop control systems
• Read and interpret a control diagram of a multi-loop system, identifying the process variable controlled and the input and output devices for each loop
• Verify that a performance problem exists by gathering information as necessary from such sources as the operator, diagrams, trend graphs, historical data, and system performance
• Locate and identify the possible causes of a performance problem in the quickest, most efficient way possible
• Divide a multi-loop system into logical divisions to isolate possible causes
• Once the problem has been located, identify and carry out or recommend appropriate corrective action
• Verify that corrective action has been taken by consulting resources and take or recommend appropriate follow-up to minimize the potential for recurrence
• Apply a systematic troubleshooting approach to its proper conclusion in ratio and cascade control as well as feedforward/feedback systems

Course 3 – Troubleshooting Distributed Control Systems

Prerequisites: This lesson is designed for participants familiar with instruments and their functions within a control loop. An understanding of the steps involved in a systematic approach to troubleshooting single loop control systems is required.

Description: This lesson applies a systematic process for identifying, isolating, and correcting process system problems to distributed control systems (DCS). Emphasis is placed on the use of DCS displays as a troubleshooting tool. System graphics such as set point displays, alarm summaries, and trend graphics are included.

Objectives:

• List the five steps in a systematic approach to troubleshooting
• Identify the set points and process variables of the components, valve positions, and alarms represented in a graphic display
• Analyze the trend of a process variable over time in a trend graph
• Identify the time, tag name, type of an alarm, and current value or status of the process variable in an alarm summary- evaluate information supplied by the system operator to determine the current condition of the system
• Apply information gathered from displays and from the operator to verify that a problem exists
• Locate and identify the cause of a performance problem in the most efficient way possible
• Take or recommend appropriate corrective action
• Verify that the problem has been corrected
• Recommend follow-up procedures to minimize the potential for recurrence
• Apply the systematic troubleshooting approach to its proper conclusion in a distillation system, batch process, cascade control system, as well as separating feed stock, and batch blending processes