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Subject to change without notice
RS232 Interface - Remote Control
Checking of the line/mains frequency triggering (50- 60Hz) is
possible, when the input signal is time-related (multiple or
submultiple) to the power line frequency ( ~ LED lights). There
is no trigger threshold visible in this trigger mode. Even very
small input signals are triggered stably (e.g. ripple voltage).
For this check, use an input of approx. 1V. The displayed signal
height can then be varied by turning the respective input
attenuator switch and its variable control.
Timebase
Before checking the timebase it should be ascertained that
the trace length is approx. 10div in all time ranges. The X-
MAG. x10 LED should not light. This condition should be
maintained until the variation ranges of these controls are
checked. Check that the sweep runs from the left to the right
side of the screen (TIME/DIV. setting to 100ms/div).
If a precise marker signal is not available for checking the
Timebase time coefficients, then an accurate sine-wave
generator may be used. Its frequency tolerance should not be
greater than ±0.1%. The timebase accuracy of the instru-
ment is given as ±3%, but it is considerably better than this.
For the simultaneous checking of timebase linearity and
accuracy at least 10 oscillations, i.e. 1 cycle every div, should
always be displayed. For precise determination, set the peak
of the first marker or cycle peak exactly behind the first
vertical graticule line using the X-POS. control. Deviation
tendencies can be noted after some of the marker or cycle
peaks. If a precise Time Mark Generator is used for checking,
Normal Triggering and LEVEL control adjustment is recom-
mended.
The signal frequency required for each time coefficient set-
ting can be determined easily by the aid of the readout. In time
measurement condition the distance of the vertical cursor
lines must be set to exactly 1 div. Then both readout informa-
tion regarding the time deflection coefficient and the time
difference show exactly the same value. After switching over
from time to frequency measurement, the readout displays
the required signal frequency in each timebase setting.
Holdoff time
The variation of the holdoff time setting can not be measured.
However, a visual check can be made if the instrument is
operated in A timebase mode. Without an input signal, set
time base to 50ns/div, use automatic peak (value) triggering.
With minimum hold off time the trace should be bright. It
should noticeably darken if the hold off time is increased to the
maximum.
Component Tester
After selecting component tester mode, a horizontal straight
line should appear immediately, when the test leads are not
connected (open circuit). The length of this trace should be
approx. 8div. With the test leads shorted together, a vertical
straight line with approx. 6div height should be displayed. The
above stated measurements have some tolerances.
Trace Alignment
The CRT has an admissible angular deviation ±5° between the
X deflection plane D1-D2 and the horizontal center line of the
internal graticule. This deviation, due to tube production
tolerances and also the influence of the earth’s magnetic
field, which is dependent on the instruments North orientation,
are corrected by means of the TR potentiometer.
In general, the trace rotation range is asymmetric. It should be
checked, whether the baseline can be adjusted somewhat
sloping to both sides round about the horizontal center line of
the graticule. With the instrument in its closed case, an angle
of rotation ±0.57° (0.1div difference in elevation per 10div
graticule length) is sufficient for the compensation of the
earth’s magnetic field.
Adjustments
As described in the
“Menu”
section, the instrument`s soft-
ware contains the submenu
“CALIBRATE”
. The following
items can be used by operators not equipped with precision
instruments. After the required warm-up time of 20 minutes,
press and hold the MENU pushbutton so that the main menu
becomes visible. In the
“CALIBRATE”
submenu the follow-
ing items can be chosen:
YAMP ( Y amplifier)
TRIGGER-AMP (trigger amplifier)
The instrument automatically adjusts and stores the adjustment
values in a non volatile memory after calling the item. During
automatic adjustments there must be no signal applied to any
input.
RS232 Interface - Remote Control
Safety
Caution:
All terminals of the RS232 interface are galvanically
connected with the oscilloscope and subsequently
with protective (safety) earth potential.
Measurement on a high level reference potential is not
permitted and endangers operator, oscilloscope, interface
and peripheral devices. In case of disregard of the safety
warnings contained in this manual, HAMEG refuses any
liability regarding personal injury and/or damage of equip-
ment.
Operation
The oscilloscope is supplied with a serial interface for control
purposes. The interface connector (9 pole D- SUB female) is
located on the rear of the instrument. Via this bidirectional
port, the instrument parameter settings can be transmitted
to, or received from a PC.
The maximum connecting cable length must not exceed 3
meters and must contain 9 lines connected 1:1. The pin
connection of the oscilloscope RS232 interface (9 pole D-SUB
female) is determined as follows:
Pin
2
Tx data (data from oscilloscope to external device)
3
Rx data (data from external device to oscilloscope)
7
CTS
(clear to send)
8
RTS (request to send)
5
Ground (reference potential - connected via the oscil-
loscope’s power cord with protective earth)
The maximum voltage swing at pin 2, 3, 7 and
8 is ±12 volt.
