PRÜFTECHNIK VIB 5.300 EX Series, Operating Instructions Manual

Page: 75 / 172

3-21
VIBXPERT 11.2010
Options
A1: Meas. setup parameters in the 'Overall values' & 'Advanced' tab
M
EASUREMENT QUANTITY
: Fixed; selection is carried out via the measure-
ment icon. Exception: The measurement quantity can be changed
for the ‘Orbit’, ‘Phase’ and ‘Coastdown’ measurement tasks.
S
AMPLE FREQUENCY
(T
IMEWAVE
R
ECORDER
): The sample frequency for the
time signal defines the maximum upper frequency and influences
the maximum measurement time.
M
EASUREMENT TIME
: Duration of an individual measurement; this
depends on the lowest frequency.
L
OWER
/U
PPER
F
REQUENCY
: Frequency range of the vibration measure-
ment. The DC component of the signal can be recorded for the
'Vibration displacement' and 'User-defined' measurement parame-
ters (lower frequency = DC, see p. 5-30).
A
VERAGING TYPE
/ N
O
.
OF MEASUREMENTS
:
Without averaging: Each single measurement is displayed.
Linear averaging: Single measurements are added and divided by
the number of averages.
Exponential averaging: The measurements are averaged exponential-
ly. The final individual measurements are more heavily weighted.
Peak hold: Highest measurement value is displayed.
O
VERLAP
: Percentage by which consecutive measurements overlap; If the
overlap is 0%, the total measurement time is: number of averages x
measurement time; the higher the overlap, the shorter the total
measurement time. For the runup / coastdown curve, the number of
usable measurements can be increased by selecting a higher overlap.
T
IME SYHNCHRONOUS AVERAGING
(P
HASE
, O
RBIT
): In this type of averaging,
the time signals of each individual rotation are averaged to reduce
non-synchronous components in the signal. The calculated phase
values are likewise averaged to increase the stability of the phase
vector. The parameters for the phase averaging correspond to the
settings under "Average type / Number of measurements' (see
above). The number of time synchronous averages is either RPM-
dependent, user-defined or unrestricted:
‘Auto’: Number of averages is a function of the rotational speed*.
‘Manual’: Number of averages can be entered (max. 254).
‘Unrestricted’: This average type is generally used for balancing.
Each individual measurement is averaged with the preceding
individual measurement. The longer the measurement takes, the
more stabile the final result. The measurement must be stopped
using the joystick.
P
ULSE PER REV
. (
WITH
RPM
MEASUREMENT
): Number of measurement
marks on the shaft or coupling.
O
RDER
(
WITH
P
HASE
, O
RBIT
, C
OASTDOWN MEASUREMENT
)
Order filter for the harmonic vibration components of the signal.
For example, only the signal components of the 1st harmonic are
filtered out and displayed by the first order filter. A half order is
used for detecting oil whirls in machines with journal bearings.
* For example, time synchronous
number of averages = 3, if speed>120
rpm.