LEYBOLD 157 89, Manual

Page: 14 / 40

Page 4
Correction for the type of gas
GAS.n2
‰ Air / Nitrogen (N
2
)
GAS.Ar
‰
Argon
Setting when shipped: Air / Nitrogen
For a more accurate determination of the true pressure
for gases other than air or N
2
in the system, the display-
ed value has to be multiplied by a factor which is cha-
racteristic for the other type of gas.
Gas Correction factorr
————————————————————————
O
2
0,88 The correction factors
He 4,7 refer to the setting
H
2
2,28 for GAS.n2 in each case.
Ne 2,16
Page 5
Software release number and locking (LOCK); refer also
to Section 2.3.9.2.
The transition from the parameter mode to the normal
measurement mode is made by pressing the key of the
desired measurement channel (TM 1, TM 2 or PM) or by
pressing the PARA key.
Parameter level 2
Parameter level 2 is called up by pressing the incre-
ment (2/13) key when parameter page 5 is being dis-
played.
Parameter level 2 contains the following:
Page 6
Units of measurement TORR, PA, MICRON, MBAR
The currently active unit flashes.
Note
The unit which is set up here, applies to all three connec-
ted measurement channels.
Supplied condition: MBAR (230 V model)
TORR (100 V or 120 V model)
Even when selecting the unit „MICRON“ for a TM chan-
nel, the pressure readings for the PM channel will always
be in „TORR“.
If the TM channels are to be set to „MICRON“ this can
not be done via the PM channel. This is only possible
when having previously selected a TM channel.
Page 7
Note
On parameter page 7 of instrument parameter level 2
there are different displays for the THERMOVAC channel
and the PENNINGVAC channel.
Page 7 for the THERMOVAC channel
Filament material of the connected sensor (FILAMENT).
FIL tu Tungsten TR 211, TR 201 and TR 205
FIL ni Nickel TR 206
FIL pt Platinum TR 216
Setting when shipped: FIL tu
Page 7 for the PENNINGVAC channel
Instrument parameter page 7 is used for automatic, pres-
sure dependent switching of the PENNINGVAC channel.
After calling up instrument parameter page 7 the display
will indicate AUTO.0 or AUTO.1
AUTO.0 The high voltage may be switched on and off
via the „HV“ key or via the external input HV-
ON. The status of the PENNINGVAC channel
is not controlled via the measurement chan-
nel TM 2.
AUTO.1 Depending on the pressure the high voltage
is switched on and off through measurement
channel TM 2. The high voltage may be swit-
ched off and on at any time by pressing the
„HV“ key or through the external input HV-
ON, provided the pressure is below 1·10
-2
mbar.
The threshold pressure for
- switching on the high voltage is:
< 1·10
-2
mbar = 7.5·10
-3
Torr = 1 Pa = 8 Micron
- switching off the high voltage is:
> 5·10
-2
mbar = 3.75·10
-2
Torr = 5 Pa = 37 Micron
In the case of automatic operation, the pressure display
is switched to the best measurement channel (TM 2/PM)
depending on the pressure. In the event of a faulty sen-
sor in channel TM 2 the high voltage has to be switched
on by the operator.
The display switches from the THERMOVAC channel to
the PENNINGVAC channel at a pressure of < 3·10
-3
mbar (2.5·10
-3
Torr) and from the PENNINGVAC channel
to the THERMOVAC channel at a pressure of > 5·10
-3
mbar.
Having actuated the keybord the change-over can be
delayed by 1 min.
Setting when shipped: AUTO.1
Page 8
Equipment parameter page 8 is used for switching the
numerical display from standard resolution (2-digit man-
tissa) to high resolution (3-digit mantissa).
Std Standard resolution 3.0
-2
HIGH High resolution 3.00
-2
For this refer to tables 3 and 4 in Section 2.10.1 or tables
7 and 8 in Section 2.10.2.
14