button (4/8) whereas pressing of the CLEAR push-button
(4/10) ends the AMP test. For accurate testing, the pre-
amplifier signal should be displayed on an oscilloscope
(BMEVS and EVS on the control assembly).
91: Burn In On <enter> Burn in test
Through this function it is possible to check the stability
of the leak detector.
The UL 200 runs a repetitive sequence composed of
Measuring (about 80 s ), Stop (30 s) and Venting (10 s).
If an internal calibrated leak is present, an internal cali-
bration is run after each 5th run during the Stop phase.
If logging of the leak rate on a printer has been selected
in menu item 15, then the current leak rate is output to
the SERIAL connection (2/10) at the end of each mea-
surement phase.
The automatic function must be active for this test (ser-
vice menu item 70).
This test may be terminated by pressing the CLEAR
push-button (4/10).
The push-buttons START, STOP and CAL are disabled
during this test.
92: Adjust Resistor Auxiliary alignment functions
After having exchanged the preamplifier, the vacuum
gauges, the EEPROMs or after having made major
modifications to the vacuum system, these functions will
assist proper alignment of the UL 200.
Three functions are available here:
- Resistor (preamplifier alignment)
- GROSS/FINE (alignment of the two vacuum ranges)
and
- Thermovac (alignment of atmospheric pressure rea-
ding).
Before, the correct second password (service menu item
50) must be entered.The automatic (menu item 70) must
be switched on.
Resistor:
In the preamplifier, the most sensitive range may be
adapted to the other ranges.
Connect a calibrated leak of 5E-7 ... 9.9E-7 mbar·l·s
-1
to
the test port (2/2) and open it.
Start the measurement process by pressing START (4/3)
and wait until the FINE vacuum range has been attained.
Select service menu item „92: Adjust Resistor“ and start
by pressing the ENTER push-button (4/8). During the
alignment process the message „Performing Adjust“ will
be displayed. As soon as the alignment process has
been completed, the LCD display will return to its initial
state „92: Adjust Resistor“. The alignment value which
has been calculated can be read off through service
menu item „59: Factor Resistor“.
GROSS / FINE:
Sensitivities alignment in the GROSS and FINE vacuum
ranges.
Connect a calibrated leak of 1E-7 ... 9.9E-7 mbar·l·s
-1
to
the test port (2/2) and open it.
Start the measurement process by pressing START (4/3)
and wait until the FINE vacuum range has been attained.
Select service menu item „92: Adjust GROSS / FINE“
and start by pressing the ENTER push-button (4/8).
At first the reminder „Connect calibrated leak <enter>“
will be displayed. When acknowledging this once more
by pressing ENTER, the alignment process will begin.
First the FINE and then the GROSS range is measured.
In order to indicate what is happening, the LCD display
indicates the message „Performing Adjust“.
After completion of the alignment process, the alignment
factor which has been calculated is displayed for about 2
s. This factor may also be displayed through service
menu item „59: Factor G/F“.
Thermovac:
Auxiliary function for alignment of the Thermovac gauges
which measure PE and PV. These are aligned at atmos-
pheric pressure. Alignment is performed through the 1
k Ω trim pot. on the I/O board.
The lower pot. is used to align the gauge for PE whereas
the upper pot. is used to align the gauge for PV.
How to proceed:
1. Switch the UL 200 off.
2. Remove the electronics cover.
3. Unscrew the fuse F6 in the left chapter of the wiring
backplane (Fig. 8).
4. Switch the instrument on and select the service
mode.
5. Enter password 2 (service menu item 50).
6. Switch the automatic function off
(service menu item 70).
7. Open valves V3 and V2b (service menu item 72); the
gauges are vented.
8. Select menu item „92: Adjust Thermovac“ and ack-
nowledge by pressing ENTER.
9. Adjust PE and PV to 8.67 V via the trim pots.
10. Switch the instrument off, insert fuse F6 and fit the
electronics cover.
During the alignment process the push-buttons START,
STOP and CAL are disabled.
The CLEAR push-button (4/10) terminates the alignment
process.
99: Change Password 2 ? Change password 2
The second password protects the service menus
against inadvertent changes.
If it is required to change this password you must first
enter the old password according to the description
26
TH 10.211/8.02 - 12/97
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