ADASH Ltd.
Adash 4300 – VA3Pro
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Time change(s)
see Runup Mode: time (the previous section)
Trigger Source:
freerun
The measurement process begins immediately (after pressing the Start button -
Analyzer mode).
external
The measurement process begins, when the external signal (voltage level higher than
defined in External Trig Level) appears on the trigger input. Such a signal may be generated when the machine
starts to work, for example. This type of signal is usually created in the control system.
manual
The measurement process begins after pressing the Start button and then the OK
button. The first press (Start) is for preparation, the second (OK) is for triggering.
manual sequential
Similar to manual but every reading for averaging must be started separately.
E.g. when AVG=10, then the OK button must be used 10 times.
amplitude
The measurement process begins when the signal level exceeds the Ampl Trig Level,
which is also set by the user in this menu. Both positive (rising edge) and negative (falling edge) levels are
accepted. E.g entering 5g will trigger on 5g. The signal amplitude is taken directly from the sensor input, no
additional filtering is applied.
Examples:
the level is set to 100mV - triggered when the rising signal goes from e.g.99mV to 101mV
the level is set to -100mV - triggered when the falling signal goes from e.g.-99mV to -101mV
tacho
The tacho is a special type of external trigger. When we say tacho, we mean a signal
(usually a TTL) which contains one pulse during one rotation of the shaft. It can also be understood as a series
of single external pulses. The measurement process begins when the external signal (a voltage level higher
than the Tacho Trig Level defined in tacho sensor) appears on the trigger input (the same as an external
item). Speed measurement, time signal averaging, aps and order analysis are only enabled when the tacho is
set.
Pretrig (%)
value in (100,-100) or user
Usually the measurement process (e.g. time signal) begins
exactly from the trigger moment. But in some applications you are also interested in knowing the signal before
the trigger. The required time should be defined in seconds, but in signal analyzers it is usually defined as
percentage part of the total signal length. When a 1 second time signal is measured and pretrigger=25, then
0,25s will be taken before the trigger and 0,75s after the trigger. Also a negative pretrigger could be used. It
means that the time signal will be taken later then the trigger pulse.
Ampl Trig Level (unit)
value
See the description of the amplitude mode (Trigger Source
section). The unit is the unit of the sensor on the selected channel (Ampl Trig Channel).
Ampl Trig Channel
( 1,2,3) The number of channels, which will be used for amplitude triggering.
External Trig Edge
rising, falling The edge used for triggering
External Trig Level[V] See the description in Trigger Source/ external
Sensors
When you connect the sensors to the instrument, you have to specify what kind of sensors you are using. The
Sensors button is displayed on most of the screens and once it is there, it is on the bottom.
Push the Menu on the main screen and select Sensors. Push the OK button. In the next menu select the
channel sensor you want to define.
