1. Purpose

This document provides a detailed step-by-step guide for the calibration of the OLCT oxygen detector, including zero calibration and span calibration procedures.

2. Calibration Preparation

2.1 Required Tools and Equipment

• Test kit
• Multimeter
• Calibration gas supply (N₂ gas for zero calibration)
• Span gas (ambient air at 20.9% O₂)
• 

2.2 Stabilization Time

⚠️ Note: After power-up, the oxygen detector requires 1 hour for stabilization before calibration can begin.

3. Calibration Procedure

3.1 Zero Calibration (Using N₂ Gas)

1. Insert the blue and green plugs of the test kit lead into the + and – multimeter sockets.
2. Connect the test kit to connector "A" on the oxygen detector.
3. Supply N₂ gas to the oxygen sensor through the calibration connector and wait for stabilization.
4. If the displayed value differs from the expected 0.4V, adjust the "0" control ("C") until exactly 0.4V is displayed.

3.2 Span Calibration (Using Ambient Air 20.9% O₂)

1. Disconnect the input/output tubes from the oxygen detector to allow atmospheric air to flow.
2. Observe the gradual increase in output voltage.
3. Confirm that the oxygen concentration displayed on the monitor is approximately 20.9%.
4. If not, adjust the output voltage to 1.505V (corresponding to 20.9% O₂) by using the span potentiometer (C) on the O₂ sensor.

⚠️ Caution: The oxygen sensor should always be calibrated at 20.9% in the atmosphere to ensure accurate readings.