Polytec OFV-3001, User Manual

Page: 89 / 101

D-5
D Functional Description of the Controller
D.4 Velocity Decoder
D.4.1 The Various Velocity Decoders
Technically it is just about impossible to attain all desirable and realizable
characteristics of the velocity decoder in a single universal subassembly. The
modular concept of the controller thus permits the use of two different velocity
decoders which can be installed simultaneously. The selection of the
decoders depends on the application. The models available are the OVD-01
and OVD-02 which feature the following characteristics.
OVD-01 The OVD-01 is a velocity decoder for applications in the acoustic frequency
range up to approximately 20 kHz. In this range, it has excellent linearity and
accuracy characteristics. With five measurement ranges from 1
to
1,000 it covers the full dynamic range of the vibrometer with high
resolution. The upper four measurement ranges can be used up to
frequencies of 50 kHz and higher while retaining their good characteristics,
however amplitude accuracy and linearity decrease with higher frequencies.
The measurement ranges 125
and 1,000 can be used from the
frequency 0 Hz (full DC capability).
OVD-02 The OVD-02 as a broad band decoder is suitable universally for almost all
applications in the frequency range up to 1.5 MHz. Four measurement ranges
from 5
to 1,000 cover most technical applications with sufficient
amplitude resolution. Characteristic is the excellent amplitude and phase
frequency response with extremely good amplitude flatness up to the highest
frequencies. In the measurement ranges 125
and 1,000 the
OVD-02 can detect DC velocity components. This is useful e.g. when
measuring on rotating discs. When setting up the sensor head, large DC
components which might otherwise overload the measurement range can
then be minimized.
mm
s
----------
V
⁄
mm
s
---------- V
⁄
mm
s
---------- V
⁄
mm
s
---------- V
⁄
mm
s
----------
V
⁄
mm
s
----------
V
⁄
mm
s
----------
V
⁄
mm
s
----------
V
⁄