Hameg HM504-2, Manual

Page: 16 / 42

Subject to change without notice
14
If addition mode (“add”) is present just one ” ^ ” symbol is
visible.
In XY mode the “0 Volt” trace position for channel I (X) and
channel II (Y) is symbolised by “triangle” symbols at the right
graticule border (Y) and above the Y deflection coefficient
display. The “triangle” symbol (s) point (s) outside the graticule
when the “0-Volt” trace position is outside the graticule.
CURS. II:
The CURSOR lines marked by the symbol “II” can be shifted
by the Y-POS/CURS. II control knob, if the CURSOR POS
LED
[7] lit.
[9] NM AT – Pushbutton with a double function and asso-
ciated 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
or automatic peak value triggering is selected.
AT:
Automatic triggering can be carried out with or without peak
capture. In both cases the LEVEL control
[11] is effective and
the trace is visible even if no signal is applied or trigger
settings are unsuitable. Signal frequencies below the
automatic trigger frequency can not be triggered as the
automatic trigger cycle starts to early for such signals.
In the automatic peak value triggering condition the LEVEL
control
[11] range is limited to the trigger signal positive and
negative peak values. Automatic triggering without peak
value detection enables the trigger point to be set outside the
signal amplitude range. In the latter case, although untriggered,
there is still a signal display.
Whether the peak value detection is active or not depends on
the operating mode and the selected trigger coupling. The
actual state is recognised by the behaviour of the trigger
point symbol when changing the LEVEL setting.
NM:
Normal triggering disables both the automatic trigger and the
peak value detection so even low frequency signals can be
displayed in a stable manner. Without suitable input signal
height, trigger coupling and LEVEL settings, no trace will be
displayed.
The last LEVEL setting of the time base is stored, then the
control again becomes active when selecting triggering after
delay DEL.MODE (“dTr”) time base mode (quasi 2
nd time
base). In combination with In “dTr” mode the LEVEL control
is operative for the “2
nd time base”.
/ \ (Slope selection):
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.
[10] TR – Trigger indicator LED.
The TR LED is lit in Yt mode if the triggering conditions are
met for the first trigger unit used in undelayed time base
[7] CURSOR POS – Pushbutton and LED.
Briefly pressing this pushbutton determines the function of
the Y-POS/CURS.I
[6] and Y-POS/CURS.II [8] controls.
If the LED is not lit the Y position control function is active.
Provided that the CURSOR lines are activated, the LED can
be switched on by briefly pressing the CURSOR POS-
pushbutton. Then the controls
[6] and [8] are switched over
from Y position to CURSOR position control CURS.I [6] and
CURS.II [8] . Briefly pressing this pushbutton once again
switches back to the Y position control function.
[8] Y-POS/CURS. II – Control knob with two functions.
This knob enables position control of channel II trace or
CURSOR line(s). Briefly pressing the CURSOR POS-
pushbutton
[7] selects the function. If the CURSOR line(s)
are not displayed the CURS. I function is not selectable.
Y-POS:
The vertical trace position of channel II can be set with this
control knob, if the CURSOR POS LED isn’t lit. In addition
(“add”) mode both, Y-POS/CURS. I [6] and Y-POS/CURS. II
[8] control knobs are active. If the instrument is set to XY
mode, this control knob is inactive and the X-POS.- knob [12]
must be used for horizontal positioning.
DC voltage measurement:
If no signal is applied at the INPUT CH II [28] , the vertical
trace position represents 0 Volt. This is the case if INPUT CH
II [28] or in addition (ADD) mode, both, INPUT CH I [25] and
INPUT CH II [28] , are set to GND (ground) [26; 29] and
automatic triggering AT [9] is present to make the trace
visible.
The trace can then be set to the vertical position best suited
for the following
DC voltage measurement. After switching
GND (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 with respect to the previous 0 Volt
position into account.
”0-Volt”-Symbol:
The READOUT indicates the “0-Volt” trace position of channel
II by a
”^” symbol to the right of the screen‘s vertical centre
line in CH II and DUAL mode. When Y-position is used, this
symbol changes to an “arrow” symbol pointing outside the
graticule just before the trace goes outside the graticule
limits.
Controls and Readout
Y-POS / CURS.I
VOLTS / DIV.
CH I CH II DEL.MODE Z-ON/OFF
Y-POS / CURS.II LEVEL X-POS.
CURSOR
POS
VOLTS / DIV.
DEL.POS.
TRIG.
SOURCE
DUAL
MENU
TIME / DIV.
20V 1mV 20V 1mV 0.5s 50ns
NM
AT
X-
MAG.
PUSH
BOTH
PUSH
LONG
INV. VAR.
VAR.
ON
OFF
VAR.
TRIG. MODE
MENU
6
7 9 8 11 13 12 10
14
15 17 19 16
24 21
22 23 20
18
VAR
CUR
VAR
TR
NM
HO
VAR
x10