x-IMU3 User Manual v0.11
April 6, 2022
3.3
Data logger capacity
3.3.1
8 GB micro SD card
Condition
Value
Notes
Default message rates
485 hours
Maximum message rates
37 hours
Table 8: Data logger capacity for 8 GB micro SD card
Notes
1. The data logging capacity is indicated for binary data messages. Capacity will be reduced for ASCII
data messages.
3.3.2
32 GB micro SD card
Condition
Value
Notes
Default message rates
1941 hours
Maximum message rates
149 hours
Table 9: Data logger capacity for 32 GB micro SD card
Notes
1. The data logging capacity is indicated for binary data messages. Capacity will be reduced for ASCII
data messages.
2. The product is supplied with an 8 GB micro SD card that can be upgraded by the user. The maximum
compatible micro SD card capacity is 32 GB.
4
Calibration
Each device is calibrated during production to achieve the specified accuracy. The calibration process uses
specialist equipment and propriety algorithms to calculate calibration parameters specific to each device.
These parameters are used by the calibration models described in the following sections to compensate for
the characteristics of each measurement source. Calibration is performed at room temperature and accuracy
will be reduced for operating temperatures that deviate from this temperature. Please refer to the calibration
certificate for specific temperature values.
4.1
System clock and RTC
The system clock and Real-Time Clock (RTC) are calibrated for errors in each clock source. The clock
calibration model is described by Equation (1) where
f
c
is the calibrated clock frequency obtained from the
uncalibrated clock frequency,
f
u
, given the value,
c
. The units of
f
c
and
f
u
are Hz.
c
is a ratio and therefore
has no units. The calibration parameter
c
for each clock can be accessed as device settings.
f
c
=
cf
u
(1)
4.2
Battery voltmeter
The battery voltmeter is calibrated for the gain of the analogue front-end and accuracy of the voltage
reference used by the Analog-to-Digital Converter (ADC). The battery voltmeter calibration model is described
12
