Dewetron DAQP-CFB2, Техническое справочное руководство

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DAQP-CFB2
Sensor Balance
Typically every strain gage sensor has a certain offset. This arises from manufacturing tolerances or from
sensor mounting. By performing a sensor balance the sensor offset can be removed on the analog side up
to 400 % of the actual range. This allows using the full range of the AD board instead of losing resolution
because of digital offset shifting. The maximum adjustable offset is mentioned in the range overview table.
The sensor offset is stored in the module and is recalculated automatically when changing the range.
Short
It switches the differential amplifier inputs IN+ and IN- to internal GND. With this function the absolute sensor
offset can be determined.
Cal
Independently from the input signal this function sets the output to 80 % of the actual range. The calibration
signal is based on the excitation voltage. So this is a simple check of the excitation voltage. Typical reason
why the excitation is not working are short circuit of the excitation at the cabling or sensor defects, too
high load for the excitation amplifier (please decrease the excitation voltage) or incorrect setting of the
synchronisation mode (no master assigned).
Filter
The DAQP-CFB has two filters. The first is a 7
th
order Butterworth filter for signal reconstruction. The cut off
frequency of this filter is automatically 0.48* carrier frequency. The second filter stage is a programmable 2
nd
order filter. The characteristic can be chosen between Bessel and Butterworth. This filter is compatible to
most other DAQP series modules. OFF-mode means bypassing the 2
nd
order filter.
450134 • DAQP/H SI /PAD Modules • Technical Reference Manual • Prin t ing version 2.3.4 • November 18, 2020