Bently Nevada 3300/50, Operation Manual

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Tachometer Maintenance
13 Threshold and Hysteresis Adjustments (Cont)
83871-01 •
8. Adjust Threshold A UP until the TRIGGER OK A LED extinguishes and the oscilloscope shows
no square wave. Note the Threshold A value at which this occurs.
9. Adjust Threshold A DOWN until the TRIGGER OK A LED comes back on, and the oscilloscope
shows the TRIGGER A square wave. Continue adjusting Threshold A DOWN until the TRIGGER OK
A LED extinguishes and the oscilloscope shows no square wave. Note The Threshold A value at
which this occurs.
10. Adjust Threshold A to a value midway between the values obtained in steps 8 and 9 above.
11. To adjust Threshold B,
press and hold the right
Alert switch o n the front
panel. T h e Threshold B
value s h o u l d r e m a i n
flashing.
12. U s e t h e (T) o r (1)
switches o n t h e System
Monitor t o a d j u s t t h e
Threshold.
13. Adjust Threshold B up
or d o w n u n t i l t h e
oscilloscope displays the
TRIGGER B square wave
(approximately 0 to 5 volts)
and the TRIGGER O K B
LED comes on.
e —
SYSTEM MONITOR
XI
63
e 3 . . 1 0
TAO-ORE-TER
2 . 1
XIKR
WARN I NG
NIS
S t e 1 4 4 4 . 1 .
co
I O C * I
A 0 Z t a n r t 0 6
I V R Y = e i l v 4 0 . 0 3 . 1
14. Adjust Threshold B UP until the TRIGGER OK B LED extinguishes and the oscilloscope shows
no square wave. Note the Threshold B value at which this occurs.
15. Adjust Threshold B DOWN until the TRIGGER OK B LED comes back on, and the oscilloscope
shows the TRIGGER B square wave. Continue adjusting Threshold B DOWN until the TRIGGER OK
B LED extinguishes and the oscilloscope shows no square wave. Note The Threshold B value at
which this occurs.
16. Adjust Threshold B to a value midway between the values obtained in steps 14 and 15 above.
17. Upon completion of the Manual Threshold procedure, reset Dip Switch SW1-5 (MT) to the "OFF"
position. This will lock the Manual Threshold values into permanent memory.
2 6
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