1.5 Calibration
Acqiris SA230E User's Manual
15
1.5 Calibration
The SA230E is factory calibrated and shipped with a calibration certificate.
The internal calibration refers to the adjustment of ADC module internal parameters, corresponding to
user selected parameters and required before starting acquisition.
Internal calibration
The internal calibration (or self-calibration) measures and adjusts the internal timing, gain and offset
parameters between the ADCs and against a precise reference.
The ADC module includes a high precision voltage source and a 16-bit DAC, used to perform the input
voltage and offset calibration.
The supplied software drivers include self-calibration function which can be executed upon user
request. The ADC modules are never self-calibrated in an automatic way, (i.e. as a consequence of
another operation). This ensures programmers have full control of all calibration operations performed
through software in order to maintain proper event synchronization within automated test applications.
For accurate time and voltage measurements it is recommended to perform a self-calibration once
the module has attained a stable operating temperature (usually reached after 20 minutes of ADC
module operation after power on).
A full internal calibration of a ADC module can be time consuming because of the many possible
configuration states. Therefore, the self-calibration is performed only for the current configuration
state, and is mandatory before making the first acquisition with given settings. Indeed the AqMD3
driver prevents an acquisition from being performed unless a self-calibration has first been completed.
Note that some configuration changes do not require a new self-calibration. To avoid unnecessary
self-calibrations, the
IAqMD3Calibration.IsRequired
IVI.NET property or the
AQMD3_ATTR_
CALIBRATION_IS_REQUIRED
IVI-C attribute should be queried.
ADC module can usually work with signals present at the channel input, or trigger input. However,
to ensure the best performance, or if the calibration is found to be unreliable (as shown by a
calibration failure status), it is recommended to remove such signals.
Similarly, when working with internal clock, it is recommended to remove external reference input
during calibration to avoid parasitic effects.
It is not recommended to perform multiple successive calibrations. If a recurrent calibration failure
occurs, in case of specific application, please contact support for advice.
Smart-calibration
The smart calibration implemented in MD3 drivers allows to save time by automatically keeping in
memory the calibration information from any self-calibration performed since the beginning of the
session. When the acquisition parameters are changed, no re-calibration of the module is necessary if
