The built-in ambient pressure compensation function of ultrasonic oxygen sensor OCS-3F260 is designed to solve the measurement error caused by altitude (atmospheric pressure) changes. The following is a detailed explanation of its importance and working principle.

1. Why does altitude (barometric pressure) change affect flow detection?

Flow sensors are mainly used to measure the mass flow or standard volume flow of a gas. However, the density of a gas varies significantly with changes in ambient pressure and temperature.

Principle: Ultrasonic flowmeter calculates the flow rate by measuring the time difference between the propagation of ultrasonic waves in the upstream and downstream, that is, the actual moving speed of gas molecules (m/s).

Question: What we need is the volumetric flow rate (e.g., SLPM, standard liters per minute) or mass flow rate (e.g., g/min) in standard conditions. Standard conditions are usually defined as 0°C and 1 standard atmosphere (101.325 kPa).

Altitude Impact: As altitude increases, atmospheric pressure decreases. At the same volume, lower pressure results in fewer gas molecules and consequently reduced gas density. Although the actual gas flow rate may remain constant, the decreased density leads to reduced gas mass passing through sensors per unit time, which translates to decreased volume when converted to standard conditions.

A simple analogy: If you breathe the same volume of air on a plain and a mountain, but at high altitude (low pressure), you will inhale fewer oxygen molecules. If the sensor only measures the volume of "one breath" without considering the air pressure, it will mistakenly think that the flow rate is the same, but in fact, the amount of oxygen delivered is different.

2. How does the environmental pressure compensation function of OCS-3F260 work?

The sensor has a built-in pressure sensor and compensation algorithm to automatically correct these errors. The workflow is as follows:

Real-time monitoring: built-in high-precision air pressure sensor to continuously monitor the current ambient atmospheric pressure value.

Data input: Real-time air pressure data (usually including temperature data, as temperature also affects density) is input into the built-in microprocessor of the sensor.

Algorithm calculation: The microprocessor runs the compensation algorithm, which converts the flow rate under actual working conditions into the standard state of volumetric flow or mass flow required by users in real time based on the gas state equation and sensor calibration parameters.

Output accurate reading: Finally, the signal output by the sensor (such as analog voltage, digital signal) is the compensated accurate standard flow value.

3. What does this mean for users? —— Huge advantage

Plug and play, no manual calculation required: users do not need to perform complex manual calculations or use external conversion tables due to location changes (e.g., from coastal to plateau), the sensor automatically completes all corrections.

Ensure measurement consistency: whether in plain or plateau, the flow reading displayed by the sensor is under the same standard (such as SLPM), to ensure that the measurement results are consistent and comparable.

Improve reliability: Avoid risks in medical or industrial processes caused by forgetting or making manual compensation errors.

Simplified system design: System integrators do not need to purchase and install additional independent air pressure sensors, simplifying circuitry and programming.

Important: Best practices

Although the OCS-3F260 has excellent automatic compensation capabilities, users should note that:

Preheat time: Ensure that the sensor is fully preheated (typically recommended>10 minutes) to stabilize the internal temperature to ensure accurate measurement of air pressure and temperature.

Avoid local pressure disturbance: Ensure that the sensor installation environment can truly reflect the ambient atmospheric pressure. Avoid installing it in a closed, pressurized or strongly turbulent box, so as to avoid the internal pressure sensor measuring the local pressure rather than the true ambient atmospheric pressure.

 sum up

The OCS-3F260's ambient pressure compensation function automatically eliminates measurement errors caused by altitude changes through the collaboration of built-in hardware (pressure sensor) and software (compensation algorithm), making it a high-performance sensor that provides stable, reliable and accurate flow measurement in different regions and environments.