- Mass alignment
- Measurement of the calibrated leak
- Zero measurement
- Calculation of the calibration factor
The calibration process takes about 25 s and has been
completed when the message „Calibration complete“
appears on the LCD display (4/2) and when an acoustic
signal can be heard.
The calibration process can be terminated by pressing
the CLEAR push-button (4/10) or by operating the CAL
push-button (4/9) once more. Depending on the opera-
ting mode - vacuum or sniffer leak detection - the cali-
bration factor „Factor Fine“ or „Factor Sniff N/QT“ is
changed.
Note for sniffer mode N and QT
During the internal calibration process, the internal sen-
sitivity of the UL 200 is calibrated. The calculated num-
ber is multiplied by the standard factor of 400 for Quick-
test operation and 1 for standard sniffer operation and
the result represents the calibration factor for the sniffer
mode.
2.7.2 External Calibration
In the case of a calibration with an external calibrated
leak, the external calibrated leak is attached to the test
sample on the system or directly to the test port (3/2).
The use of calibrated leaks is permissible which produce
a reading in the range from 5·10
-9
to 9.9·10
-4
mbar·l·s
-1
.
Note
In the case of external calibration on systems where the
pumping speed of the pump system is high, the circum-
stances may be such that a calibrated leak can not be
detected owing to the high partial flow factor. In such
cases a calibrated leak with a higher leak rate must be
used.
For external calibration it is required that the UL 200 is
running in the measurement mode.
Select the measurement mode by pressing the START
push-button, for example.
When the green light emitting diode on the hand unit
(5/3) is on continuously, or when the LCD display indica-
tes a measured value, then press the CAL push-button
(4/9).
The running process may be terminated by pressing the
CLEAR push-button (4/10) or by pressing the CAL push-
button (4/9) once more. In contrast to the fully automatic
internal calibration process, the external calibration pro-
cess is interactive. After it has been started, the LCD dis-
play (4/2) will indicate messages which inform the ope-
rator about the process and ask him to run further ope-
rations.
Displayed message Action required by the
(4/2) operator
————————————————————————–
Autotune none
Open Cal-Leak <enter> Open the calibrated leak and
acknowledge by pressing
ENTER.
Cal-Leak: Enter the value of the mantis-
(z.B.) 3.5 E-07 mbar·l·s
-1
sa and acknowledge by pres-
sing ENTER.
Cal-Leak: Enter the exponent and ack-
3.5 E-07 mbar·l·s
-1
nowledge by pressing EN-
TER.
Signal Stable ? <enter> Wait until the readout (5/4) is
stable and then press EN-
TER.
Performing mass
alignment
Acoustic signal after
completion none
Close Cal-Leak <enter> Close the calibrated leak and
then press ENTER.
Signal Stable <enter> Wait until the readout (5/4) is
stable and then press EN-
TER.
Calibration finished The measurement may now
be continued.
The calibration factor is calculated on the basis of a two-
point measurement (open calibrated leak and closed
calibrated leak).
Note
For proper determination of the calibration factor a mini-
mum difference between open and closed leak is requi-
red. If this difference is too small then the error message
„E78: CAL difference too small“ will appear. In such a
case use a larger calibrated leak.
Depending on the operating mode - vacuum or sniffer
leak detection - the calibration factor „Factor Fine“ or
„Factor Sniff N/QT“ is changed.
If the calibration is run in the partial flow mode where the
partial flow valve is open, then the calibration factor „Fac-
tor F/P“ (see description for menu item 59) is changed.
2.7.3 External Calibration for
Sniffer Applications
For sniffer applications, the UL 200 should be calibrated
externally. For this it is required that the UL 200 is run-
ning in the measurement mode and that a sniffer has
been connected to the test port (3/2). The instrument
must be running in the sniffer mode „2: Mode Sniff NOR-
MAL“ or „2: Mode Sniff QT“.
29
TH 10.211/8.02 - 12/97
To Next Page
Loading...
