Air Quality Sensor ENS160 with equal values for TVOC and ETOH

Sensors
1

I use the Indoor Air Quality Sensor (ENS160, SEN-20844) and some other sensors connected to the DataLogger IoT (DEV-22462, firmware 01.02.00) via Qwiic. When reading the air quality parameters, the values for ENS160.TVOC and for ENS160.ETOH are always identical. Eg. (Column 7 and 8 are identical):

RV8803.Read ISO8601 DateTime (Y,OPT4048.CIEx,OPT4048.CIEy,OPT4048.CCT,OPT4048.Lux,ENS160.AQI,ENS160.TVOC,ENS160.ETOH,ENS160.eCO2,ENS160.Temp Comp,ENS160.Humidity Comp,SHTC3.Humidity (%RH),SHTC3.Temperature (C)

2024-10-15T21:14:35,0.494,0.373,1990.557,6,1,24,24,400,23.819,44.164,66.523,23.286

2024-10-15T21:14:36,0.449,0.406,2825.014,6,1,0,0,400,23.819,44.164,66.151,23.267

2024-10-15T21:14:37,0.432,0.429,3276.878,6,1,0,0,400,23.819,44.164,65.873,23.275

2024-10-15T21:14:37,0.432,0.429,3276.878,6,1,0,0,400,23.819,44.164,65.554,23.350

2024-10-15T21:14:38,0.437,0.425,3157.467,6,1,0,0,400,23.819,44.164,65.370,23.422

2024-10-15T21:14:38,0.458,0.397,2606.449,6,1,0,0,400,23.819,44.164,65.483,23.414

2024-10-15T21:14:44,0.485,0.368,2032.776,7,1,24,24,400,23.819,44.164,62.698,23.264

2024-10-15T21:14:45,0.485,0.368,2032.776,7,1,0,0,400,23.819,44.164,62.553,23.243

2024-10-15T21:14:45,0.487,0.366,2002.021,7,1,0,0,400,23.819,44.164,62.354,23.235

2024-10-15T21:14:46,0.487,0.366,2002.021,7,1,1,1,400,23.819,44.164,62.150,23.248

2024-10-15T21:14:46,0.491,0.363,1949.545,7,1,1,1,400,23.819,44.164,62.090,23.251

2024-10-15T21:14:47,0.489,0.365,1978.156,7,1,11,11,400,23.819,44.164,62.037,23.259

2024-10-15T21:14:47,0.489,0.365,1978.156,7,1,11,11,400,23.819,44.164,61.872,23.256

2024-10-15T21:14:48,0.489,0.365,1978.156,7,1,0,0,400,23.819,44.164,61.801,23.235

2024-10-15T21:14:48,0.489,0.365,1978.156,7,1,0,0,400,23.819,44.164,61.682,23.227

2024-10-15T21:14:49,0.489,0.365,1978.156,7,1,18,18,400,23.819,44.164,61.605,23.200

2024-10-15T21:14:49,0.489,0.365,1978.156,7,1,18,18,400,23.819,44.164,61.617,23.222

2024-10-15T21:14:50,0.488,0.363,1972.120,7,1,16,16,400,23.819,44.164,61.526,23.176

2024-10-15T21:14:50,0.495,0.368,1953.360,7,1,16,16,400,23.819,44.164,61.472,23.214

2024-10-15T21:14:51,0.495,0.368,1953.360,7,1,18,18,400,23.819,44.164,61.360,23.163

2024-10-15T21:14:51,0.390,0.445,4160.824,7,1,18,18,400,23.819,44.164,61.332,23.200

2024-10-15T21:14:52,0.431,0.401,2799.283,5,1,18,18,400,23.819,44.164,61.390,23.171

2024-10-15T21:14:52,0.448,0.401,2799.283,5,1,11,11,400,23.819,44.164,61.390,23.190

2024-10-15T21:14:53,0.543,0.332,1819.159,5,1,11,11,400,23.819,44.164,61.300,23.190

2024-10-15T21:14:53,0.497,0.388,2075.423,7,1,16,16,400,23.819,44.164,61.379,23.155

2024-10-15T21:14:54,0.470,0.367,2181.740,7,1,16,16,400,23.819,44.164,61.273,23.179

2024-10-15T21:14:54,0.486,0.356,1939.271,7,1,18,18,400,23.819,44.164,61.279,23.168

2024-10-15T21:14:55,0.483,0.360,1998.144,7,1,18,18,400,23.819,44.164,61.209,23.160

2024-10-15T21:14:55,0.483,0.360,1998.144,7,1,16,16,400,23.819,44.164,61.244,23.168

2024-10-15T21:14:56,0.483,0.360,1998.144,7,1,16,16,400,23.819,44.164,61.292,23.168

2024-10-15T21:14:56,0.484,0.358,1968.217,7,1,20,20,400,23.819,44.164,61.358,23.198

2024-10-15T21:14:57,0.491,0.363,1949.545,7,1,20,20,400,23.819,44.164,61.175,23.160

2024-10-15T21:14:57,0.491,0.363,1949.545,7,1,18,18,400,23.819,44.164,61.181,23.155

2024-10-15T21:14:58,0.487,0.366,2002.021,7,1,18,18,400,23.819,44.164,61.273,23.139

2024-10-15T21:14:58,0.484,0.357,1961.909,7,1,24,24,402,23.819,44.164,61.277,23.144

2024-10-15T21:14:59,0.484,0.357,1961.909,7,1,24,24,402,23.819,44.164,61.274,23.168

2024-10-15T21:14:59,0.484,0.357,1961.909,7,1,16,16,400,23.819,44.164,61.312,23.168

2024-10-15T21:15:00,0.480,0.361,2023.475,7,1,16,16,400,23.819,44.164,61.308,23.125

2024-10-15T21:15:00,0.487,0.366,2002.021,7,1,17,17,400,23.819,44.164,61.263,23.163

2024-10-15T21:15:01,0.450,0.392,2678.550,7,1,17,17,400,23.819,44.164,61.326,23.171

Is this a bug? And if it is, is there a workaround to read the correct values of both parameters?

Thanks in advance,

Rudi

2

I’m guessing there’s a typo in the library; create an issue here Issues · sparkfun/SparkFun_Indoor_Air_Quality_Sensor-ENS160_Arduino_Library · GitHub

3

I’m copy/pasting from the issue in Github, because I know that’s a little inconvenient for some.

Unfortunately there’s nothing wrong with the library. According to the datasheet the ETOH values are just the TVOC values, because the TVOC values are calibrated for ethanol! You can see that here:

“Virtual Mirror of the ethanol-calibrated DATA_TVOC Register”

image
image838×348 67.9 KB

…and again here “DATA_ETOH (0x22) = DATA_TVOC”

image
image920×156 34.9 KB

I also left notes within the library noting that the values share the same register. They are in fact the same…

#define SFE_ENS160_DATA_TVOC 0x22
// TVOC Data - shares register with ethanol data
typedef struct
{
    uint8_t tvoc_msb : 8;
    uint8_t tvoc_lsb : 8;
} sfe_ens160_data_tvoc_t;

#define SFE_ENS160_DATA_ETOH 0x22
// Ethanol Data - shares register with TVOC data
typedef struct
{
    uint8_t etoh_msb : 8;
    uint8_t etoh_lsb : 8;
} sfe_ens160_data_etho_t;

Hope this helps.

1 Like
4

Ah, interesting! I did not expect that lol

5

Dear wonder_boom,

thank you for this information!!! Yes, it helps to sleep well again:-)! I had never thought of anything like that, even though I had actually taken a look at the ENS160 data sheet (but obviously I didn’t read it carefully enough).

Sorry for my unnecessary request!

Kind regards, Rudi