SENSIRION SCD4 Series, Manual, Page: 13 / 24

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Table 18 : perform_forced_recalibration I
2
C sequence description
Write
(hexadecimal)
Input parameter: Target CO
2
concentration Response parameter: FRC-correction
Max.
command
duration [ms]
length [bytes] signal conversion length [bytes] signal conversion
0x362f 3
word[0] = Target
concentration [ppm CO
2
]
3
FRC correction [ppm CO
2
] =
word[0] – 0x8000
word[0] = 0xffff in case of
failed FRC
400
Example: perform forced recalibration, reference CO
2
concentration is 480 ppm
Write 0x362f 0x01e0 0xb4
(hexadecimal) Command Input: 480 ppm CRC of 0x01e0
Wait 400 ms command execution time
Response 0x7fce 0x7b
(hexadecimal) Response: - 50 ppm CRC of 0x7fce
3.7.2
s
et_automatic_self_calibration_enabled
Description : Set the current state (enabled / disabled) of the automatic self-calibration. By default, ASC is enabled. To save the
setting to the EEPROM, the persist_setting (see chapter 3.9.1) command must be issued.
Table 19 : set_automatic_self_calibration_enabled I
2
C sequence description.
Write
(hexadecimal)
Input parameter: ASC enabled Response parameter: -
Max. command
duration [ms]
length [bytes] signal conversion length [bytes] signal conversion
0x2416 3 word[0] = 1 → ASC enabled
word[0] = 0 → ASC disabled
- - 1
Example: set automatic self-calibration status: enabled
Write 0x2416 0x0001 0xB0
(hexadecimal) Command ASC enabled CRC of 0x0001
3.7.3 get_automatic_self_calibration_enabled
Table 20 : get_automatic_self_calibration_enabled I
2
C sequence description
Write
(hexadecimal)
Input parameter: - Response parameter: ASC enabled
Max. command
duration [ms]
length [bytes] signal conversion length [bytes] signal conversion
0x2313 - - 3 word[0] = 1 → ASC enabled
word[0] = 0 → ASC disabled
1
Example: read automatic self-calibration status: disabled
Write 0x2313
(hexadecimal) Command
Wait 1 ms command execution time
Response 0x0000 0x81
(hexadecimal) ASC disabled CRC of 0x0000