ZMOD4450 Datasheet

© 2021 Renesas Electronics Corporation

9

June 30, 2021

7. Gas Sensor Module Characteristics

Additional information about sensitivity and sensor module influences are explained in the following sections. All graphs and information show

the typical responses that are to be expected from the ZMOD4450 Gas Sensor Module upon exposure to a variety of test conditions. For more

information, including application notes, white papers, blog, and manuals, visit the ZMOD4450 webpage.

7.1 Characteristics for Typical Gas Stimulation

The ZMOD4450 also allows controlling an external device, such as an active air filter or ozone generator, based on the air quality changes.

Although the sensor module is not selective to an individual gas, it detects a variety of volatile organic and sulfur compounds. Figure 2 shows

the sensor module response to the most relevant organic and sulfur-based gases associated with food quality. The ZMOD4450 is also sensitive

to additional gases (e.g., Octanal, Hexaldehyde, and Ammonia); however, sensitivity data is not illustrated for these gases in the figure.

Figure 2. Gas Response to Typical Gases and Levels of Expected Refrigeration Gases

The sensor module outputs are raw resistance measurements and an algorithmic calculation of the refrigeration air quality change (RAQ), which

indicates a total air quality change over time inside the refrigeration application. Therefore, the ZMOD4450 algorithms give a relative output

signal. RAQ is a ratio of concentrations and defined as the following:



< 1: Improvement of air quality, overall gas concentration is falling



= 1: No change in air quality



> 1: Deterioration of air quality, overall gas concentration is rising

In addition, a control state is given, which shows the status of a user-defined threshold.

Renesas provides firmware and algorithms, which allow the ZMOD4450 to learn the refrigeration environment. The gas sensor module will

immediately respond to changes in the refrigeration air by detecting changes in the relative gas concentrations. When the user-defined threshold

is exceeded, an I/O control signal (trigger) based on the algorithm output can be used to control an external device.

1E+4

1E+5

1E+6

1E+7

0.01

0.1

1

10

Concentration [ppm]

Air

Dimethyl Sulfide

Ethylene

Hydrogen Sulfide

Isopropyl Acetate

Trimethyl Amine