Hameg Instruments LCR-Bridge HM8118 Handbuch Seite 47

6 Calibration
Prior to any measurement an open circuit, resp. a short circuit
calibration should be performed in order to avoid measurement
errors. The open/short circuit calibration compensates for the
effects of parasitic impedances of the connections to the compo-
nent under test. A load calibration is especially suitable in order
to take an impedance measured before the measurement of the
unknown into account. With a calibration it is possible to com-
pensate measurement connections and other parasitic effects
(capacitive impedances). Any calibration must be performed at
the actual measuring frequency.
In order to achieve the best accuracy all three calibration steps
should be carried out in the same set-up and the same environ-
mental conditions used for the measurement of the unknown,
especially the placement of the leads should remain identical. The
measurement leads should be far from any metallic objects and
the hands of the operator. In order to initiate the calibration steps
the respective parameter must be set to ON by pressing SELECT
3
and calling the menu CORR. The parameters OPEN / SHORT
/ LOAD can now be set using the arrow buttons
6
with the knob . The calibration procedure takes a few seconds;
as soon as it has been performed successfully, the display of the
selected calibration message will disappear.
11
12
13
Fig. 6.1: Buttons for the calibration
From the firmware version 1.35 upwards, the HM8118 offers
the possibility to automatically extend the OPEN and SHORT
calibration steps over all 69 available frequencies. Select the
menu item CORR and change the entry MODE from SGL (single)
to ALL. Then leave the menu und press the pushbuttons OPEN
resp. SHORT on the front panel.
Now the HM8118 will perform an automatic calibration of
OPEN and SHORT at all 69 frequencies. This procedure will
take appr. 90 seconds. After a successful calibration a short
beep will occur.
For further details on OPEN resp. SHORT calibration see section
6.1 resp. 6.2.
6.1 Open circuit calibration procedure
In order to perform a correct open circuit calibration there must
be nothing connected to the measurement leads! To start the
calibration function press the button OPEN
The display will show „Opening: (measuring frequency)".
If no calibration can be performed successfully, an error mes-
sage will be displayed. The open circuit calibration is possible
if the impedance is >10 kΩ.
Gerätevorderseite
1 POWER (Taste)
Netzschalter; Netzanschluss auf der Geräterückseite
6.2
2 GATE (LED)
In order to perform a correct short circuit calibration the mea-
Die GATE-LED leuchtet während der gesamten Dauer einer
surement leads must be shorted directly with no components
Messung. Dies entspricht der gewählten Torzeit und einer
attached. To start the calibration press the SHORT button
Synchronisierungszeit.
The display will show „Shorting (measuring frequency)".
3 REMOTE (LED und Taste)
Die REMOTE–LED leuchtet, sobald das Gerät über die Schnitt-
If no calibration can be performed successfully, an error mes-
stelle angesprochen wird. Um zur manuellen Betriebsart
sage will be displayed. The short circuit calibration is possible
zurückzukehren, ist die REMOTE-Taste zu drücken.
if the impedance is <15 Ω or the resistance <10 Ω.
Display (LCD-Anzeige)
4
Anzeige des Messergebnisses und verschiedener Zusatzin-
6.3
formationen
5 ESC (Taste)
After the selection of the desired measuring function, e.g.
Escape-Taste in der Menüsteuerung
the calibration with a known load is performed separately for the
6 ENTER (Taste) main display LOADM and the second display LOADS (S stands
for "sub"). It is recommended to choose the value of this load
Enter-Taste in der Menüsteuerung
close to the expected value of the DUT (= Device Under Test).
7 SELECT (Taste) Press the button LOAD
Menüaufruf bzw. Auswahl eines Menüpunkts
The display will show „Load Cal: [measuring frequency]".
7
8    (Tasten) or
If no calibration can be performed successfully, an error mes-
Pfeiltasten zur Menüsteuerung und Parametereinstellung
sage will be displayed. The LOAD calibration is possible for
impedances and resistances within the full measurement range.
9 Drehgeber
Drehknopf zur Parametereinstellung
10 GATE TIME (Taste)
Einstellung der GATE-Zeit
11 LEVEL B (Taste)
Einstellung des Triggerlevels von Kanal B
12 LEVEL A (Taste)
Einstellung des Triggerlevels von Kanal A
13 16 1 : 10 (Taste)
Eingangssignalabschwächer, Gesamtabschwächung 100-fach
8
Änderungen vorbehalten
11
.
Short circuit calibration procedure
Procedure of the calibration with a known
load
13
to start the calibration.
Any calibration with a known load requires that
values were entered in both reference memories
(LOADM and LOADS). (In the above example a
value for the expected inductance in LOADM and a
value for the expected quality factor Q in LOADS.
The latter is only valid for the selected measuring
frequency.)
Subject to change without notice
Taste DC leuchtet
Taste DC aus
C a l i b r a t i o n
15 Slope (Taste)
Durch Drücken dieser Ta
Leuchtet die Taste, wird a
die Taste unbeleuchtet, e
Flanke.
17 50 Ω (Taste)
12
.
Zuschalten eines 50 Ω-W
sung bei 50 Ω-Systemen
18 LP 50 kHz (Taste)
Tiefpassfilter zur Vermei
bei niederfrequenten Sig
TRIG (LEDs) Triggeri
19 23
INPUT A, INPUT B (B
20 22
Messsignaleingänge
L-Q
AUTO TRIG (Taste) ,
21
Aktivierung des Auto-Trig
wenn die automatische T
24 INPUT C (SMA-Buchse)
Messsignaleingang 100
25 RESET · V
Taste mit Doppelfunktio
1. Durch Drücken diese
unterbrochen, die Anze
gestartet.
2. Bei Einstellung des Trig
der eingegebene Wert m
26 TRIG · GHz/s (Taste)
Taste mit Doppelfunktio
1. Auslösen einer Messu
2. Bei Einstellung der Gat
eingegebene Wert mit de
27 HOLD · mV (Taste)
Taste mit Doppelfunktio
1. Durch Drücken diese
angezeigte Messwert ein
47
= D
= AC