By using FIGARO's evaluation chamber (EC01), it is possible to easily measure the sensitivity of a gas sensor without the need for expensive equipment or devices.

This article explains how to acquire the analog output of a gas sensor using the evaluation chamber and evaluation module.

Easy Setup with the Evaluation Chamber (EC01)

Required Equipment

To acquire data from a gas sensor using the evaluation chamber (EC01), the following items are required:

Mounting and Wiring the Gas Sensor

Evaluation module (EM26)

This time, we will use three types of semiconductor-type gas sensors from FIGARO Engineering: "TGS2600 (gas sensor for detecting air contamination)," "TGS2602 (gas sensor for detecting air contamination and odors)," and "TGS2603 (gas sensor for detecting air contamination and offensive odors)."

First, install these gas sensors to their respective evaluation module (EM26). As shown in the figure above, make sure that the protruding part of the sensor (indicated by the arrow) is oriented toward the connector side.

The photo above shows the semiconductor gas sensors mounted on the evaluation modules (EM26).

Next, mount the evaluation modules (EM26) with the gas sensors onto the Test board included with the evaluation chamber (EC01).

At that time, make sure to insert the module firmly all the way in, aligning the pin numbers on the module with those on the 5-pin (white) connector on the test board.

The gas sensors are now mounted on the module measurement board.

Place the module measurement board with the gas sensors into the evaluation chamber (EC01).

Next, as indicated by the arrows in the photo above, connect ① the power supply cable (white, 2-core) to the connector, and connect ② the flat-ribbon cable (50-core) inside the chamber to the connector on the module measurement board.

Finally, connect the flat cable (50-core) <Photo ①> extending from the evaluation chamber (EC01) to the data logger.

Although there is a connector (black) at the end of the flat cable, if an extension flat cable (Omron's XG4E-5031) is not available, cut off the connector with scissors. <Photo ②>

Then, referring to the EC01 instruction manual, strip the insulation from the required signal wires of the flat cable to prepare for connection. <Photo ③>

In this case, we are using a data logger to acquire the analog outputs of multiple gas sensors simultaneously. Connect the necessary signal wires from the flat cable, along with the GND line and the +5V line, to the positive (+) and negative (−) terminals of the data logger respectively as shown in the photo.

In the data logger used here, the positive terminals are on the upper row and the negative terminals are on the lower row.

Wiring is now complete.

Data Acquisition

Now, let's log the output of the three types of semiconductor-type gas sensors in a normal indoor environment by following the steps below.

How to Acquire Data Using the Evaluation Module (EM26) and Evaluation Chamber (EC01)

(1) Plug the AC power cable (black) of the evaluation chamber (EC01) into an outlet.

(2) Turn on the data logger and set the sampling conditions (in the figure above: 1-second interval, 0 to +5V range, and display of channels 1 to 4 only).

(3) Start logging in advance.

(4) Turn on the power switch of the chamber.

(5) The analog output from the gas sensors will be recorded in the data logger. To stop logging, press the "STOP" button.

Saving Analog Output Data

Once you have confirmed that the analog output data has been recorded in the data logger, save it to your PC in CSV format. When you open the CSV data in Microsoft Excel, it will look like the sample shown above.

Types of gas sensors

Let's try graphing the data opened in Microsoft Excel. From the graph, you can see that the output from the semiconductor-type gas sensors in clean air undergoes a significant initial change immediately after the power is turned on.

Advantages of Analog Output

Analog output-type gas sensors offer the advantages of stable measurement and easy, fast transmission of measurement results to other devices.

In addition, because changes in sensor output can be measured in fine detail and almost in real time, unlike digital output which only provides ON/OFF signals, it is possible to closely observe the increase and decrease in sensor output.

Please make use of the resources on FIGARO Engineering website, in which you can find easy-to-understand animations explaining the detection principles and usage of gas sensors.

Learn About Gas Sensors Through Videos »