The chips sense a relative value for total VOC (TVOC), or equivalent CO2(eCO2).
Two things have changed :
- The 48 hour initial burn-in period have been cut to an hour for three of the five operating modes.
- Air quality indication range has been increased:
Max eCO2 value has been raised from from 8,194ppm to 32,768ppm
Max eTVOC value has been raised from 1,187ppb to 32,768ppb.
The second change is to allow the chips to be used in sensors within air cleaners and air purifiers intended for use in more polluted indoor environments and, according to the firm, and the first means that OEM customers can greatly reduce or even eliminate any burn-in process implemented at the factory and still provide end users with immediate out-of-the-box operation when integrated into an indoor air quality monitoring application.
Both chips include a micro hotplate inside, with a metal oxide gas sensing layer. CCS0801 operates over -5 to +50°C and has an analogue output and needs to be connected to an external microcontroller. It’s update comes in the form of up-dates software libraries.
CCS811 operates over -40 to +85°C, has a microcontroller built-in, and provides an I2C digital output. It’s update is a change to internal firmware.
A third change to the software is that users get the ability to to configure the clean air baseline value, so, said AMS, OEMs can save and restore their own baseline values when the CCS8xx sensor is powered off and re-started in a polluted environment, and the intervals between automatic baseline correction can be programmed by OEMs.
The tests indicate that CCS801 and CCS811 meet the sensitivity and performance tolerances allowable by “all relevant standards”, said AMS.
On the subject of indoor pollution, AMS marketing manager Paul Wilson said: “According to the US Environmental Protection Agency, there is growing evidence that indoor air can be more polluted and expose to a greater health risk than outdoor air pollution. Since people spend on average 90% of their time indoors, there are enormous benefits both to health and comfort to the use of devices based on the CCS801 or CCS811 which monitor the air quality in the home, workplace or car.”