www.sensirion.com

Version 1.1 – April 2021

17/22

3.10 Low power single shot (SCD41)

In addition to periodic measurement modes, the SCD41 features a single shot measurement mode, i.e. allows for on-demand

measurements.

The typical communication sequence is as follows:

1.

The sensor is powered up.

2.

3.

4.

Steps 2-3 are repeated as required by the application.

values. After a power cycle, the initial two single shot readings should be discarded to maximize accuracy. The idle current in

between measurements is 0.15 mA (typ.), respectively 0.2 mA (max.). The energy consumed per single shot typically is 243 mJ

(296 mJ max.).

As for the periodic measurement modes, the automatic self-calibration (ASC) is enabled per default in single shot operation.

The automatic self-calibration is optimized for single shot measurements performed every 5 minutes. Longer measurement

intervals will result in less frequent self-calibration sequences. Note that no self-calibration is issued if the sensor is power-cycled

between single shot measurements Please consult Chapter 3.7 for a detailed description of the automatic-self calibration and

the corresponding commands.

3.10.1 measure_single_shot

using the read_measurement command (chapter 3.5.2).

Table 28: measure_single_shot

Write

(hexadecimal)

Input parameter: -

Response parameter: -

Max. command

duration [ms]

length [bytes]

signal conversion

length [bytes]

signal conversion

0x219d

-

-

-

-

5000

Example: measure single shot

Write

0x219d

(hexadecimal)

Command

3.10.2 measure_single_shot_rht_only

Description: On-demand measurement of relative humidity and temperature only. The sensor output is read using the

Table 29: measure_single_shot_rht_only

Write

(hexadecimal)

Input parameter: -

Response parameter: -

Max. command

duration [ms]

length [bytes]

signal conversion

length [bytes]

signal conversion

0x2196

-

-

-

-

50

Example: measure single shot, RH and T output only

Write

0x2196

(hexadecimal)

Command