Measurement Range Rng; Measurement Speed Spd - Hameg R&S HM8118 Benutzerhandbuch

Instrument Functions
Contrary to the internal preload, in this example an exter-
nal DC preload is generated on the R&S®HM8118 back pa-
nel. Component and measurement mode are identical to
the example with the internal preload. The external DC pre-
load is generated for the R&S®HM8118 by a power supply
unit (here: R&S®HMP2020) in this example. The voltage is
applied to the power supply unit at 20V and the current is
limited to 250mA.
Fig. 7.5: Activate external BIAS preload
The C-R mode is also activated as function and the BIAS
key is used via knob
10 6
cimal point) to select the voltage value. Press the BIAS
MODE key to select the EXT (= external) function via
24
knob. Use the BIAS /
BIAS preload.
Fig. 7.6: Activate external BIAS preload
Example for internal bias current BIAS:
The process for an internal bias current is similar to that
for an internal preload. In this case, the L-R or L-Q function
is selected and any given inductance is connected to the
bridge. Use the BIAS key via knob
10
(decimal point) to select the value for the in-
7
ternal bias current. The BIAS /
vate the internal BIAS bias current.
Fig. 7.7 shows an example for a typical waveform of a bias
current that is adjustable to a maximum value in connec-
tion with a connected load.
54
or arrow keys
7
key to activate the external
26
or the arrow keys
6
key is used to acti-
26
Fig. 7.7: Maximum setting for bias current in connection with the
connected load (typical waveform)

7.1.4 Measurement Range RNG

The measurement range can be selected automatically or
manually. If the measurement range is changed, the inter-
nal measurement circuit (replacement circuit) will be mo-
dified and internal relays will be switched. Therefore, a
change in the measurement range depends on multiple
(de- factors, such as phase angle, impedance, measured va-
lue, etc.
The measurement range can be set manually via knob
in the range of 3 Ω to 500 kΩ. In the SETUP menu, use the
arrow keys
the knob (editing mode) and select the desired measure-
ment range via knob. Press the knob again to confirm the
selected value. Use the AUTO/HOLD key to then switch
between automatic (AUTO/HOLD key is illuminated) and
manual measurement range selection.
If the measuring instrument permanently toggles between two
measurement ranges (limit of the automatic measurement range)
or if the component to be measured is known, select the manual
measurement range selection (see chapter 6).

7.1.5 Measurement Speed SPD

The measurement speed can be set in three increments:
❙ SLOW (slow),
❙ MED (medium)
❙ FAST (fast).
In the SETUP menu, use the arrow keys
select the SPD function to set the measurement speed,
press the knob
6
ment speed via knob. Press the knob again to confirm the
selection.
The number of measurements for a continuous triggering
(CONT) is approximately 1.5 per second at the SLOW set-
ting, 8 per second at MED or 14 per second at FAST. The
to select the RNG function, press
7
(editing mode) and select the measure-
6
to
7