Traceability in Calibration Procedures

Mastering Pressure Transmitter Calibration – Step-by-Step Guide Calibrating a pressure transmitter is a fundamental task in instrumentation, ensuring accurate and reliable process measurements. Whether in oil & gas, power generation, or manufacturing – precision matters. Here’s a comprehensive calibration procedure: 1. Isolate the Transmitter Ensure the transmitter is safely isolated from the process line to avoid exposure to live pressure during calibration. 2. Connect Calibration Tools Attach a pressure source (hand pump or pressure calibrator) and a reference standard calibrator with known traceability. 3. Apply Pressure in Steps Apply incremental pressure points: 0%, 25%, 50%, 75%, and 100% of the transmitter’s calibrated range. 4. Record and Compare Readings Note the transmitter’s output (in mA or digital signal) at each step and compare it to the reference standard. 5. Adjust Zero & Span If deviation is found, use a HART communicator or local buttons to fine-tune the zero and span settings. 6. Verify and Repeat Reapply the pressure points to verify accuracy after adjustments. The transmitter should now be within acceptable tolerance. 7. Document Everything Record the “As-Found” and “As-Left” data, calibration date, technician name, and instrument tag. Good documentation ensures traceability and compliance. Why it matters: Accurate calibration improves process efficiency, reduces downtime, and ensures safety. From the field: With over a decade of hands-on experience in instrumentation and control—especially in power generation plants—I’ve seen firsthand how precise calibration directly impacts operational stability, safety, and energy efficiency. Small errors can lead to big consequences. Have you done a calibration recently? Share your tips or tools you use in the comments! #Instrumentation #Calibration #PressureTransmitter #PowerGeneration #ProcessAutomation #MaintenanceExcellence #Engineering #FieldExperience

🔧 7 Steps Calibration Procedure for Differential Pressure (DP) Transmitters : Ensuring accurate measurement is key to process safety, product quality, and operational efficiency. Here's a simplified yet professional approach to calibrating a DP transmitter, aligned with NIST traceability and IEC 61508 functional safety standards: ✅ Step 1: Prepare Tools Required Calibrated pressure source (hand pump) Digital pressure calibrator or reference manometer Multimeter, power supply (24V), HART communicator Manufacturer’s datasheet and calibration certificate ✅ Step 2: Safety First Follow site-specific LOTO (Lockout-Tagout) procedures Depressurize lines and isolate process connections Wear appropriate PPE and ensure proper venting ✅ Step 3: Setup the Calibration Bench Connect transmitter to the pressure source and reference device Apply 24 VDC power and ensure correct wiring ✅ Step 4: Perform Calibration Apply zero pressure (LRV) → Adjust Zero Apply Span pressure (URV) → Adjust Span Repeat in 25% steps (0%, 25%, 50%, 75%, 100%) ✅ Step 5: Check Linearity Record readings at each pressure point in both ascending and descending order Compare against reference device Ensure readings are within manufacturer’s accuracy specs ✅ Step 6: Post Calibration Checks Reconnect to process carefully Remove test equipment Confirm transmitter is responding correctly in DCS or PLC ✅ Step 7: Calibration Report Preparation Document: Instrument tag As-found and as-left values Date/time, environmental conditions Name and signature Ensure traceability to NIST standards Align with IEC 61508 if part of a SIS loop Let’s raise the standard in field instrumentation #Instrumentation #DCS #Calibration #ProcessControl #Maintenance #Automation #DPTransmitter #IEC61508 #NIST

How to fulfill the traceability of measuring equipment required by ISO 13485? I regularly see uncertainty on how to fulfill the traceability requirements for measuring equipment which are specified in ISO 13485, clause 7.6a). This clause requires, that measuring equipment must be calibrated “traceable to international or national standards.” But what does this mean and how can you implement it? Simply said, the calibration chain must be traceable back to the national standard. This means that the calibration of your equipment must ultimately link to the national standard which is in Switzerland METAS. How can you achieve this traceability? ➡️ Collect Certificates: You could gather all the calibration certificates for each step in the calibration chain back to the national standard—though this can be time consuming. -or- ➡️ Use an Accredited Calibration Lab: An easier option is to ensure that your calibration certificate comes from a lab that is accredited by an ILAC signatory body. This accreditation ensures that the calibration is traceable, and you don't need to go further down the chain. My tip: If you’re ISO 13485 certified, always use an accredited calibration lab and make sure their accreditation mark is available on the certificate. If you found this helpful, feel free to Repost 🔁, follow me Beat Keller for more insights, and click the 🔔 to stay updated.