LEYBOLD 157 89, Manual

Page: 10 / 40

2.3.2 Digital display
The digital display (3/3) is used to digitally display the
pressure with respect to the selected measurement unit.
In case of Torr, Pa and mbar the readout is composed of
mantissa and exponent.
When selecting Micron the readout is composed only of
5 digits. Above 99000 Micron the readout automatically
changes over to Torr. 1.0·10
2
Torr is indicated, and all
subsequent readings will be in Torr.
When the pressure drops below to 9.0·10
1
Torr the dis-
play will then automatically return to the unit Micron. The
CM 31 will then display 90000 Micron and all subsequent
readings will be in Micron again. The lowest displayed
reading is 1 Micron.
2.3.3 Measurement units
Located to the right of the digital display is the display for
the pressure units (3/4). Only that unit will be indicated
which has previously been selected via parameter page
6.
When selecting the Micron pressure unit the reading will
change between Micron and Torr depending on the pres-
sure; (see Section 2.3.2).
2.3.4 Status display area
The status display area (3/1) for the measurement chan-
nels is located between the area of the keys and the
pressure display.
Trigger and equipment modes are indicated in the status
display area (3/1). These are related to the keys below
which are used to select the measurement channel. An
overview giving the arrangement of the trigger and
equipment status modes is shown in Fig. 3. Details are
described briefly in the following.
Trigger 1 (< 1 >)
The triggers as indicated in the status display area and
by the status displays relate to the measurement chan-
nel which is selected by the key below.
If the left arrow of the trigger display is on, this indicates
that the actual pressure is lower than the trigger set
point.
If the right arrow of the trigger display is on, this indica-
tes that the actual pressure is higher than the trigger set
point.
Trigger 2 (< 2 >)
The same as for trigger 1 also applies to trigger 2.
FAIL
The word FAIL comes on in the event of a sensor failure;
see Section 2.9.
DISP
DISP indicates the channel, the values of which are just
being displayed. Here for example TM 1, TM 2 or PM.
HV
The HV (high vacuum gauge) message comes on, when
the high voltage for the PM channel is present.
CORR
The CORR message comes on, when a different type of
gas other than the standard gas „air / nitrogen“ has been
10
Fig. 3 Partial view of the front panel
Key to fig. 3
1 Status display area
2 Bar graph display
3 Digital display
4 Measurement units