Hameg HM404-2.02, Руководство пользователя

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13
Subject to change without notice
Controls and Readout
After switching GD (ground) off and selecting DC input
coupling, a DC signal applied at the input changes the
trace position in vertical direction. The DC voltage then
can be determined by taking the deflection coefficient,
the probe factor and the trace position change in respect
to the previous 0 Volt position into account.
”0 Volt” Symbol:
The determination of the ”0 Volt” position is not necessary
if the readout is switched on and the software setting
”DC Ref. = ON” is selected in the ”SETUP” submenu
”Miscellaneous” . Then the ”
⊥ ⊥⊥ ⊥⊥
” symbol to the left of the
screen‘s vertical center line always indicates the ”0 Volt”
trace position in CHI and DUAL mode.
The ”0 Volt” position symbol (
⊥ ⊥⊥ ⊥⊥
) will not be displayed in
XY and ADD (addition) mode.
(9) Y-POS. II - Control knob.
The vertical trace position of channel II can be set with
this control knob. In ADD (addition) mode both ( Y-POS. I
and Y-POS. II ) control knobs are active.
DC voltage measurement:
If no signal is applied at the INPUT CHII (30) , the vertical
trace position represents 0 Volt. This is the case if INPUT
CHII (30) or in addition (ADD) mode, both INPUT CHI (26)
and INPUT CHII (30) , are set to GD (ground) and automatic
triggering (AT (10)) is present to make the trace visible.
The trace then can be set to vertical position which is
suited for the following
DC voltage measurement.
After switching GD (ground) off and selecting DC input
coupling, a DC signal applied at the input changes the
trace position in vertical direction. The DC voltage then
can be determined by taking the deflection coefficient,
the probe factor and the trace position change in respect
to the previous 0 Volt position into account.
”0 Volt” Symbol:
The determination of the ”0 Volt” position is not necessary
if the readout is switched on and the software setting
”DC Ref. = ON” is selected in the ”SETUP” submenu
”Miscellaneous” . Then the ”
⊥ ⊥⊥ ⊥⊥
” symbol to the right of
the screen‘s vertical center line always indicates the ”0
Volt” trace position in CHI and DUAL mode.
The ”0 Volt” position symbol (
⊥ ⊥⊥ ⊥⊥
) will not be displayed in
XY and ADD (addition) mode.
(10) NM - AT -
Pushbutton with a double function and associated NM -
LED.
NM - AT selection:
Press and hold the pushbutton to switch over from
automatic (peak value) to normal triggering (
NM -LED
above the pushbutton lit) and vice versa. If the LED is
dark, automatic (peak value) triggering is selected.
Whether the peak value detection in automatic trigger
mode is automatically activated or not, depends on the
trigger coupling setting (
TRIG.MODE ). The way the
trigger point symbol in the readout responds on different
LEVEL control knob settings indicates the situation:
1. If the trigger symbol can not be shifted in the vertical
direction when a signal is not applied or the signal
height is not sufficient, the peak value detection is
active.
2. Under the condition that the trigger point symbol
cannot be shifted in such a way that it leaves the signal
display on the screen, the peak value detection is
active.
3. The peak value detection is switched off if the trigger
point can be set outside the maximum peak values of
the signal, thus causing an untriggered signal display.
Slope selection:
Briefly pressing this pushbutton selects which slope of
the signal is used for triggering the time base generator.
Each time this pushbutton is briefly pressed, the slope
direction switches from falling edge to rising edge and
vice versa.
The current setting is displayed in the readout by a slope
symbol. The last setting in undelayed time base mode is
stored and still active if triggered
DELAY (DTR) time base
mode is selected. This allows for a different slope setting
for the triggered
DELAY (DTR) time base mode.
(11)TR - Trigger indicator LED.
The TR LED is lit in Yt mode if the triggering conditions
are met. Whether the LED flashes or is lit constantly
depends on the frequency of the trigger signal.
(12)LEVEL - Control knob.
Turning the LEVEL knob causes a different trigger point
setting (voltage). The trigger unit starts the time base
when the edge of a trigger signal crosses the trigger
point. In most Yt modes the trigger point is displayed in
the readout by the symbol on the left vertical graticule
line. If the trigger point symbol would overwrite other
readout information or would be invisible when being
set above or below the screen, the symbol changes
and an arrow indicates in which vertical direction the
trigger point has left the screen.
The trigger point symbol is automatically switched off
in those modes where there is no direct relation
between the trigger signal and the displayed signal. The
last setting in undelayed time base mode is stored and
still active if triggered
DELAY (DTR) time base mode is
selected.
This allows for a different level setting for the triggered
DELAY (DTR) time base mode.
(13) X-POS. - Control knob.
This control knob enables an X position shift of the
signal(s) in Yt and XY mode. In combination with X
magnification x10 (Yt mode) this function makes it
possible to shift any part of the signal on the screen.