Combine Multiple Sensors for One Value

Individual sensors tell you what is happening at specific monitoring points. Sometimes, however, you need to combine those readings to get the value you want: an average temperature across several locations, or the difference in pressure between two points.

Quicklime virtual sensors let you use readings from multiple sensors in a calculation and produce a single output value. In this video tutorial, we demonstrate two examples: averaging temperature readings and calculating differential air pressure.

Watch the Video Tutorial

Follow the video below to see how to select sensor inputs and configure a virtual sensor calculation in Quicklime. The examples below explain how the calculations work and where they can be useful.

What Is a Calculated Virtual Sensor?

A physical sensor measures a condition at its location. A calculated virtual sensor uses existing sensor readings as inputs and applies a formula to produce another value.

For example, three temperature sensors provide three separate measurements. A virtual sensor can add those readings together and divide the result by three, giving you one average temperature.

The original readings still provide local detail, while the calculated value gives you an additional way to interpret them.

Example 1: Average Multiple Temperature Sensors

When monitoring a room, rack, or equipment area, you may want an average temperature from several measurement points.

For three temperature sensors, the calculation is:

Average Temperature = (Temperature 1 + Temperature 2 + Temperature 3) ÷ 3

Suppose the sensors report:

In Quicklime, select the temperature sensors as inputs to your virtual sensor and configure the calculation shown in the tutorial. Adjust the divisor to match the number of sensors included.

Choose Inputs That Represent the Area

Use sensors that are relevant to the condition you want to summarize. For example, averaging several rack inlet temperatures gives you a different measurement from averaging a mixture of inlet and exhaust temperatures.

All inputs should use the same temperature unit.

An average is useful for understanding general conditions, but it can hide a hot spot. Continue monitoring individual readings alongside the average so that one unusually high temperature is not overlooked.

Example 2: Calculate Differential Air Pressure

A virtual sensor can also subtract one pressure reading from another to calculate the pressure difference between two measurement points.

The calculation is:

Differential Pressure = Pressure A − Pressure B

For example:

The result shows that Pressure A is 15 Pa higher than Pressure B.

Keep the Subtraction Order Consistent

The order of the inputs determines the sign of the result. If Pressure A is lower than Pressure B, the calculation returns a negative value.

Choose a clear convention, such as “Room Pressure − Reference Pressure,” and name the virtual sensor accordingly. This helps users understand what positive and negative readings mean.

Both pressure inputs must use compatible units and a common reference. The sensors must also have sufficient accuracy and resolution for the pressure difference you want to measure. Subtracting two readings does not improve the accuracy of the underlying sensors.

Check Your Calculation

After configuring the virtual sensor, compare its output with a manual calculation using the input readings.

For a temperature average, add the readings and divide by the number of inputs. For differential pressure, subtract the second reading from the first in the same order used in Quicklime.

Use a descriptive name and the correct output unit so the calculated value is easy to interpret. For example:

• Average Rack Inlet Temperature — °C

• Room-to-Reference Pressure Difference — Pa

Also check how the calculation behaves if an input sensor becomes unavailable, so you understand when the output can be relied upon.

Get More Information from Your Sensor Readings

Quicklime virtual sensors let you turn several measurements into one useful calculated value. Whether you need an average temperature or a pressure difference, the calculation provides another view of the conditions you are monitoring.