User Manual EE895
Miniature Sensor Module for CO
2
, Temperature and Barometric Pressure | 20
4.5.3. CO
2
Parameter Settings
The CO
2
parameter settings are non-volatile since they are stored in the flash memory.
Function
code
Register
address
1)
[HEX]
Description
Unit
Note
0x06
0x1450
CO
2
measuring interval
S
16 bit integer unsigned
Scale 1:10. Example: 150 = 15 seconds
Range 100…36 000
Default 15 s
0x1451
CO
2
filter coefficient*)
-
16 bit integer unsigned
Range 1…20
Default: 4
0x1452
CO
2
customer offset
ppm
16 bit integer signed
Range -32 786…32 785
Default: 0 ppm
1) Register address starts from 0
Tab. 18
CO
2
parameter settings
*) The EE895 features an exponential moving average filter which to a certain degree suppresses the influence
of short-term CO
2
variations onto the output CO
2
data. The filter coefficient is user selectable and affects the
response time of the EE895. A higher filter coefficient leads to smoother output data and to longer response time,
see figure Fig. 12. Fig. 13 shows the number of samples required to reach 63% or 90% of a CO
2
step as function
of the filter coefficient.
Fig. 12 Step response vs. samples
