Philips pm2521 Operating Manual page 47

4 9
Selection of the trigger level
- S e l e c t t h e + o r - t r i g g e r l e v e l b y d e p r e s s i n g p u s h b u t t o n + / - .
R e m a r k :
Signats which are higher or lower than the circuit zero oÍ the PM 2521 (O terminal) can be triggered with the
+ or - trigger level respectively.
In + trigger level mode the PM 2521 triggers on positive cÍossings of the trigger level. In - trigger level mode the
PM 2521 triggers on negative crossings of the trigger level.
+ TRIGGE R
L E V E L O
Fig. 20. Trigger level selection in peak
5 T 3 0 r 5
8202?6
voltage measu rement mode.
-
A d j u s t t h e t r i g g e r l e v e l w i t h t h e t h u m b w h e e l u n t i l t h e G A T E i n d i c a t i o n o n t h e d i s p l a y i s i g n i t e d .
R e m a r k :
The trigger level can be adjusted between zero and end of range.
The voltage reading on the display indicates the height of the trigger level.
l f t h e i n p u t s i g n a l c a n n o t b e t r i g g e r e d , p r o c e e d a s f o l l o w s :
-
S e l e c t a n o t h e r t r i g g e r l e v e l p o l a r i t y d e p r e s s i n g p u s h b u t t o n + l - a n d t r y t o t r i g g e r a g a i n .
-
C h e c k w h e t h e r t h e i n p u t s i g n a l i s l o w e r t h a n 7 . 5 % o f t h e e n d o f r a n g e v a l u e o f t h e s e l e c t e d t r i g g e r l e v e l
r a n g e . S i g n a l s l o w e r t h a n 7 . 5 % c a n n o t b e t r i g g e r e d a c c u r a t e l y .
-
S e l e c t a h i g h e r t r i g g e r l e v e l r a n g e b y d e p r e s s i n g p u s h b u t t o n U P a n d t r y t o t r i g g e r a g a i n .
Measurement of the peak voltage
-
A d j u s t t h e t r i g g e r l e v e l w i t h t h e t h u m b w h e e l u n t i l t h e G A T E i n d i c a t i o n o n t h e d i s p l a y j u s t s w i t c h e s o n o r
o f f . T h e v o l t a g e o f t h e t r i g g e r l e v e l e q u a l s t h e p e a k v o l t a g e o f t h e i n p u t s i g n a l .
E x a m p l e s :
G A T E A T + 1 . 0 0 0 V
r 1 V
+ T R I G G E R L E V E L
R A N G E 2 V
_ T R I G G E R L E V E T
R A N G E 2 V
G A T E A T
- 1 . 0 0 0 V
G A T E A T + O 5 . O 0 V
+ 5 V
T T R I G G E R L E V E L
R A N G E 2 0 V
0
T R I G G E R P O I N T S { - _ )
T R I G G E R P O I N T S ( + + )
Fig. 21. Peak voltage measurements.
5 T 3 0 1 7