Bently Nevada 3300/50, Operation Manual

Page: 70 / 122

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Tachometer Maintenance 83871-01
113 I Threshold and Hysteresis Adjustments (Cont)
3. When adjusting t h e Transducer A Manual
Threshold, connect an oscilloscope to the TRIGGER
A Test Point (TA) located behind the front panel.
When adjusting the Transducer B Manual Threshold,
connect the oscilloscope to the TRIGGER B Test
Point (TB).
NOTE: An oscilloscope is helpful, but not necessary.
NOTE: The buffered transducer input signals can be
observed by connecting the oscilloscope to the
coaxial connecters on the front panel.
4. T h e machinery should b e running and t h e
transducers should be properly connected to the
Signal Input Module (Section 27,28, or 29).
5. To adjust Threshold A,
press a n d hold t h e left
Alert switch on the front
panel. T h e Threshold A
value remains flashing.
6. U s e t h e ( r ) o r ( I )
switches o n t h e System
Monitor t o adjust t h e
Threshold.
7. Adjust Threshold A up
or d o w n u n t i l t h e
oscilloscope displays the
TRIGGER A square wave
(approximately 0 to 5 volts)
and the TRIGGER O K A
LED comes on.
e.—
TACMCMUER
12)
1:0C
A
XOCR
0
TRIGGER B
TEST P O I N T
T B
S T
T A
P H
TRIGGER A
TEST POINT
BUFFERED I N P U T SIGNALS
CD
CD
ACHOMMM
-12 1
a m A
see ~ U A L
-10,8
%OCR I
. 0 : : = 2 1 0 0
• 0
0
1 1 0 . 1 9 . e 0 M A I . O U C E P P 5
2 5