BME688: Switching between different modes using BSEC

[g_sharma]

Hi there, 

I'm currently using BME688, and it's library,BSEC, to prepare a demo for classifying fire/smoke against normal air.

My question is two part: 

1. Which power mode (scan, ULP, LP or CONT) should I run the sensor on to get the most accurate results for fire detection?
   
   
2. Secondly, the integration guide for BSEC mentions that "To achieve best gas sensor performance, the user shall not switch between different modes during the lifetime of a given sensor". Is there a way that we can switch between different modes while the sensor is in opreation, in order to get multiple fields of data. If not, is there a valid explanation as to why the integration guide has adviced against switching between 2 different modes? 

I'll be highly obliged if my questions can be addressed, and valid explanations can be received from any expert in the community. 

Thanks. 

[BSTRobin]

Hi g_sharma,

If you want to determine fire/smoke based on IAQ values, you can set it to LP and ULP modes.
If you want to determine fire/smoke through gas estimate, you can set it to SCAN mode.
LP/ULP and SCAN modes cannot be used simultaneously.
The current architecture of BSEC software does not allow switching between different modes

[g_sharma]

Hi BSTRobin, 

Thanks for your response. 

According to your understanding, which mode would best fit for fire detection? I'd also like to know if CONT mode could come handy, or if it can be used simultaneously with other modes. 

According to what I have understood from your answer is that BSEC would not allow to simultaneously run or switch between any 2 (or more) different modes, right? 

Secondly, can you please explain me the state_save() and config_load() functions that come with the BSEC library? What do they mean and how to implement them? Also, can this functionality enable us to run two different modes and have them in a single binary file? Or is it still not possible? 
I'd highly appreciate any responses to this, preferably in simple terms. 

Thanks

[BSTRobin]

Hi g_sharma,

The choice of mode depends on the environmental changes during fire detection.

The current BSEC software does not support switching between different modes.

The running status of BSEC can be saved to non-volatile memory in function state_save() , so that there is no need to recalibrate the sensor on the next boot.
After powering on, the BSEC state previously saved to non-volatile memory can be loaded through the config_load() function instead of restarting sensor calibration.