Version 2.1
en MBI 46.31 operating instruction.docx
Issue date: 01/2022
Page 35 of 42
You can further optimize the system depending on the measuring task by
similar methods to those described in chapter 5.5.1 and 5.5.2. For instance,
curve 4 shows the linearity characteristic of the measuring chain if the
measuring amplifier is set to minimum deviation at the beginning and the end of
the measuring range.
To set the measuring amplifier according to these instructions,
the linearity curve of the displacement sensor must be
determined. As an option for all MESSOTRON displacement
sensors, you can receive test reports with the linearity curve
(according to 5.5.1 Optimization with the smallest possible error
in the zero point).
5.6 Improving the noise rejection
The MBI 46.31 CF measuring amplifier series is suitable for use in highly
dynamic applications. As delivered, the (3 dB) dynamic bandwidth is 1/10 of the
carrier frequency. If only slow processes are to be measured, the dynamic
bandwidth may be reduced for a better noise rejection performance.
•
By fitting capacitor C4, you can additionally filter the output signal.
•
First start with some 10 nF and then increase the capacitance incrementally.
•
Make sure that the output signal is not distorted with the fast processes in
your application. Otherwise you must select a capacitance value for C4 of
the next smaller size.
The actual capacitance value required for setting a specific
dynamic bandwidth depends on the carrier frequency and the
associated standard filtering of the measuring amplifier. Use a
capacitance decade box (approx. 10...1000 nF) to determine the
correct capacitors.
NOTE
NOTE
