ZMOD4510 Datasheet

© 2021 Renesas Electronics Corporation

10

June 30, 2021

5.3 Operation Mode 2: OAQ 2nd Generation

during its fast sample rate of 2 seconds. The second generation OAQ algorithm is tuned to ozone detection and the cross-sensitivity response

to NO2 is reported as less than 25 AQI even at NO2 levels up to 200ppb. The AQI output is according to the EPA standard and differentiated

between 1 hour and 8 hours exposures (concentration dependent). For operation outdoors it is recommended to follow the EPA standard, which

is called “EPA AQI” in the output files. However, for fast changing environments (e.g., during evaluation, testing, and system checks), it is

recommended to use the “FAST AQI” signal, which is the same AQI calculation based on a 1-minute average. The algorithm is tailored for best

accuracy in the typical environmental range of 20 to 100ppb and can report up to 500ppb. AQI values above 500 are considered beyond the

AQI.

5.4 Sensor Module Algorithm and Firmware

To operate the ZMOD4510, the software and libraries provided by Renesas should be used. The algorithm for the user’s microprocessor always

uses the raw output signals from the ZMOD4510, which are resistances, to determine the level of gases present. Depending on the

microprocessor and compiler used, the firmware and its algorithms require 10 to 20 kB flash size. All algorithms feature an automated baseline

correction function, ensuring that the module can learn from its environment and distinguish elevated levels of gases under all conditions. The

proprietary metal oxide (MOx) used in the sensor ensures that the sensor module can respond effectively to changing ozone and nitrogen

dioxide levels, respectively, during long-term operation. Therefore, the user focus should always be on the relevant output parameters: the air

quality index (AQI) and/or ozone concentration.

For implementing the sensor module in a customer-specific application, detailed information on the programming is available. More information

and guidance on the firmware integration, architecture, and supported platforms are available in the ZMOD4510 Programming Manual – Read

Me. Code Examples in C and additional firmware descriptions for API, HAL, libraries, etc., are included at no cost in the downloadable firmware

package from the ZMOD4510 product page.