Hameg HM 1004-3 Series, Manual

Page: 13 / 36

13
Subject to change without notice
Controls and Readout
(8) TRS
The instrument contains a trace separation function which
is required in the alternate timebase mode to separate
the B timebase trace from the A timebase in Y direction.
Consequently this function is only available in alternate
timebase mode. After the TRS pushbutton was pressed
once the LED related to that pushbutton is lit.
The Y-POS. I control knob is then operative as vertical
position control for the trace of the B timebase. The
maximum position shift is approx. +/- 4 div. Without a
change of the
Y-POS. I control the trace separation
function is switched off automatically after approx. 10
seconds. The trace separation function can also be left by
pressing the TRS pushbutton.
(9) Y-POS. I - Control knob with a double function.
Y-Position channel I:
The vertical trace position of channel I can be set with this
control knob. In ADD (addition) mode both (Y-POS. I and
Y-POS. II) control knobs are active.
Y-Position B-trace in alternate timebase mode:
In alternate timebase mode, this control knob can be
used to separate the B timebase trace from the A
timebase trace.
Please note TRS (8) .
DC voltage measurement:
If no signal is applied at the INPUT CHI (27), the vertical
trace position represents 0 Volt. This is the case if INPUT
CHI (27) or in addition (ADD) mode, both INPUT CHI (27)
and INPUT CHII (31), are set to GD (ground) and auto-
matic triggering (AT (11)) is present to make the trace
visible. The trace then can be set to vertical position
which is suited for the following DC voltage measure-
ment.
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 neces-
sary 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.
(10)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. If the instrument
is set to XY mode this control knob is inactive and the X-
POS. knob must be used for a horizontal position shift.
DC voltage measurement:
If no signal is applied at the INPUT CHII (31), the vertical
trace position represents 0 Volt. This is the case if INPUT
CHII (31) or in addition (ADD) mode, both INPUT CHI (27)
and INPUT CHII (31), are set to GD (ground) and auto-
matic triggering (AT (11)) is present to make the trace
visible. The trace then can be set to vertical position
which is suited for the following DC voltage measure-
ment.
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 neces-
sary 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.
(11)NM - AT - (SLOPE)
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 timebase generator.