Yearly calibration services for portable analysers involve several key steps to ensure accuracy and reliability. These include an initial inspection to check for damage, battery health, and firmware updates. Sensor calibration involves resetting and verifying sensor accuracy using known gas concentrations. Gas flow and pressure are checked, along with functional tests for alarms, response time, and leak detection. A calibration certificate is issued upon completion, ensuring compliance with standards. Recommendations for sensor replacement or repairs are provided if needed, and data logging is backed up. Optional services include on-site calibration, loaner devices, and annual service contracts.