RTD Commissioning Checklist

• Commissioning a Resistance Temperature Detector (RTD) involves multiple steps to ensure proper installation, calibration, and functionality. 
• This comprehensive checklist includes safety considerations, pre-commissioning checks, commissioning procedures, and documentation requirements to ensure a smooth and efficient process.

Step 1: Preparation Documents for RTD Commissioning

• Instrument Loop Diagrams (ILD): Detailed loop diagrams showing all components, wiring details, terminal numbers, and signal flow from RTD sensor to control system input.
• RTD Data Sheets: Manufacturer data sheets detailing resistance, tolerance, temperature range, and accuracy.
• Transmitter Data Sheets: Data sheets for transmitters, including input range and output specifications.
• Wiring Diagrams: Detailed diagrams showing wiring connections, routes, and termination points.
• Specification Sheets: Complete specifications for all related equipment.
• Loop Folders: Organized folders containing all loop-related documents and calibration records.
• P&ID (Piping and Instrumentation Diagrams): Diagrams showing the process flow, piping, and instrumentation details.
• Instrument Location Layout: Drawings showing the physical location of each RTD within the process area.
• Hookup Drawings: Detailed installation drawings showing how the RTD is connected to the process and associated instrumentation.

Step 2: Safety Considerations

Before beginning RTD commissioning, ensure proper safety protocols are in place:

• Work Permits and Site Safety Procedures: Obtain necessary work permits and follow site-specific safety procedures. 
• Ensure that all personnel are aware of and comply with these procedures.
• Personal Protective Equipment (PPE): Wear appropriate basic  PPE including a hard hat, safety glasses,. Ensure all PPE is in good condition and fits properly.
• Safe Work Area: Establish a safe work area and use barricades to prevent unauthorized access. 
• Clearly mark the work area and communicate the boundaries to all personnel on-site.
• Lockout/Tagout Procedures: Ensure proper lockout/tagout of electrical and process equipment to prevent accidental energization. 
• Verify that all energy sources have been isolated and locked out according to the procedure.
• Ensure a safety shower and eye wash station are accessible. 
• Keep a fire extinguisher nearby in case of electrical fires. 
• Check that emergency equipment is operational and that personnel know its location and how to use it.

Step 3: Pre-Commissioning Checks

Verify RTD Type and Wiring Configuration

• Ensure the RTD type (e.g., 100Ω platinum, 10Ω copper) matches the specification sheet and control system configuration. 
• Verify the RTD coefficient  ‘alpha’ value (resistance change per °C) is correct.  Click here for RTD Temperature Coefficient Calculation
• Double-check these values against the project specifications and manufacturer data.
• Confirm the wiring configuration (2-wire, 3-wire, 4-wire) is as specified and ensure no jumpers have been used to alter the wiring configuration. 
• Verify that the wiring matches the control system input configuration.

Click here for Converting 2-Wire and 3-Wire RTDs into 4-Wire RTDs

Inspect RTD Installation

• Verify the RTD is installed at the correct location per the P&ID and specification. 
• Ensure the RTD is properly immersed in the process to the specified depth. This ensures accurate temperature measurement.
• Check that the RTD is securely mounted and will not move during operation. Confirm that the installation is mechanically robust and that vibration or process flow will not affect the sensor.
• Confirm the RTD leads are routed correctly and not damaged. 
• Inspect the entire length of the lead wires for any signs of physical damage or wear.

Verify Thermowell Condition

• Ensure the thermowell is clean, free of debris, and has good thermal conductivity. 
• Inspect the internal and external surfaces for cleanliness and damage.
• Check that the RTD makes proper contact with the thermowell and that any thermal paste used is clean and effective. Proper contact ensures accurate temperature readings.
• Confirm the thermowell is the correct material and pressure rating for the process. 
• Verify this against process conditions to ensure compatibility.

Check RTD Continuity and Resistance

• Disconnect the RTD leads at both ends and check for continuity between each lead. Use a multimeter to verify there are no breaks in the wiring.
• Measure the resistance between each lead and confirm it matches the RTD type (e.g., 100Ω for Pt100). Document the measured resistance for reference.
• Check the insulation resistance between the RTD leads and thermowell/process connection. 
• Ensure there is no unintended continuity that could cause measurement errors.

Click here for RTD Calculator: Converting Process Temperature to measured Output Resistance

Inspect Wiring and Terminations

• Verify the RTD wiring is properly routed in conduit or cable trays. 
• Ensure the wiring is protected from mechanical damage and environmental exposure.
• Check that wire terminations are tight and connections are clean. Loose or dirty connections can cause unreliable readings.
• Ensure the wiring is labeled correctly at both ends and that the wiring shields are properly grounded. Proper labeling aids in future troubleshooting and maintenance.
• Inspect the cable glands on the RTD and its transmitter for proper tightness to prevent moisture ingress. Proper sealing ensures long-term reliability of the connections.

Inspect RTD Transmitter (if applicable)

• Verify the transmitter is the correct model and range for the RTD. Ensure it matches the project specifications and process requirements.
• Check that the transmitter is properly mounted and accessible. Proper mounting ensures the transmitter is not subject to excessive vibration or environmental exposure.
• Ensure the transmitter is configured for the correct RTD type and wiring. Check the configuration settings against the RTD specifications.
• Confirm the transmitter output matches the RTD input (e.g., 4-20mA). Verify this by measuring the output signal and comparing it to the expected value based on the RTD resistance.
• Inspect the cable glands on the transmitter for proper tightness. Proper sealing prevents moisture ingress and ensures long-term reliability.

Inspect Power Supply and Grounding

• Verify the transmitter power supply is the correct voltage and capacity. 
• Check the power supply specifications against the transmitter requirements.
• Check that the power supply is properly grounded. Proper grounding ensures the transmitter operates correctly and safely.
• Ensure the transmitter is grounded per manufacturer recommendations. Follow the manufacturer’s guidelines to ensure proper grounding and avoid ground loops.

Step 4: Commissioning Procedure

RTD Signal Simulation

• Inject a test resistance signal simulating the RTD at the field wiring termination. Use a precision decade box or similar device to simulate the RTD.
• Verify the correct instrument and point number respond in the control room. Check that the control system correctly identifies the test signal.
• Confirm the displayed temperature matches the injected resistance value. Document the results for comparison with actual RTD readings.

Click here for How to simulate RTDs and Thermocouples using Multifunction calibrator?

Calibrate RTD Transmitter

• Inject a series of resistance values spanning the RTD range. Use a calibrated resistance source to ensure accuracy.
• Measure the transmitter output at each point and compare it to the input resistance. Document the output readings and compare them to the expected values.
• Adjust the transmitter zero and span to match the input to output. Fine-tune the transmitter settings to ensure accurate temperature measurement.
• Document the as-left calibration data. Record the final transmitter settings and output readings for future reference.

Click here for How to Calibrate RTD transmitter?

Verify Control System Integration

• Confirm the RTD input is properly mapped to the control system. Check that the input signal is correctly assigned in the control system software.
• Verify the temperature value is displayed correctly on HMI screens. Ensure the displayed value matches the transmitter output.
• Check that the RTD can be used for control, alarm, and shutdown functions. Verify that the control system responds correctly to the RTD input.
• Ensure the RTD input passes through the full range without saturation. Check for any anomalies or limitations in the input signal range.

Perform Loop Check

• Simulate a temperature change and verify the control loop responds as expected. Check the control system’s response to the simulated input.
• For control loops, stroke the final control element (valve, damper, etc.) and confirm proper operation. Ensure the control element responds correctly to the temperature input.
• For alarm and shutdown trip loops, verify the logic activates at the correct setpoint. Test the alarm and shutdown functions to ensure they operate as intended.

Click here for 8 Steps RTD Calibration Procedure

Validate Process Response

• With the process at operating conditions, compare the RTD reading to a calibrated reference thermometer. Use a calibrated reference thermometer to verify the RTD accuracy.
• Ensure the RTD reading is within the specified accuracy of the reference. Document any discrepancies and investigate potential causes.
• Document the as-found calibration data. Record the initial RTD readings for future comparison.

Click here to know about RTD Tolerance Calculation

Finalize Commissioning

• Update the RTD calibration records with the as-found and as-left data. Maintain accurate records for future reference.
• Ensure the RTD tag matches the P&ID and control system documentation. Verify that all documentation is consistent and up-to-date.
• Obtain sign-off from the commissioning team and operations personnel. Ensure all stakeholders agree that the commissioning process is complete.

Step 5: Commissioning Documentation

Commissioning Procedures

• Develop detailed procedures for each commissioning activity. Include safety precautions, equipment needed, and step-by-step instructions. 
• Obtain approval from the project manager and operations before use.

Commissioning Checklists

• Create checklists to ensure all pre-commissioning and commissioning steps are completed. 
• Include spaces to record data, observations, and sign-offs. Maintain the checklists as part of the commissioning records.

Calibration Records

• Document the as-found and as-left calibration data for each RTD and transmitter. 
• Include the instrument tag, range, input/output values, and technician signature. Maintain the calibration records per company policy, typically 5-10 years.

Commissioning Reports

• Prepare a final commissioning report summarizing the results. Include the completed checklists, calibration records, and any issues encountered. Obtain signatures from the commissioning team and operations manager.

Turnover Package

• Assemble a turnover package with the commissioning documentation. Include the P&ID, instrument data sheets, and manufacturer manuals. 
• Deliver the package to operations for inclusion in the plant documentation system.

Downloadable RTD Commissioning Checklist

Ensure a smooth RTD commissioning process with this detailed downloadable excel checklist. It covers preparation, safety, pre-commissioning, and commissioning steps.

Click here for RTD Calculator: Converting Measured Resistance to Process Temperature