Inficon Ecotec E3000, Technical Handbook

Page: 82 / 146

4-24
Equipment Settings
ki
n
a
22
e c
h
ap
te
r 4
.fm
te
chn
ica
l ha
nd
boo
k
(1
20
6)
1…3V: 1
st
decade
3…5V: 2
nd
decade
5…7V: 3
rd
decade
7…9V: 4
th
decade
Thus a leak rate range of 4 decades will be output by way of an analogue signal.
The four decades are set through the value and the unit of measurement for the
trigger level.
The software of the Ecotec E3000 will set the output voltage in such a manner that
the trigger level itself will always be set within the second decade (i.e. within the
range of 3 to 5 Volts).
Examples :
The following table has been provided to clarify the way in which the output voltage
represents the leak rate.
Further examples:
For a trigger level of 2 g/a a leak rate of 8 g/a is represented by an output voltage of
4.81 V:
U = 3 + 2·log 8
(The factor of 2 is used since one decade is spread over 2 Volts. The summand of 3
is used because the trigger level will always be within the range of 3 to 5 V).
LOG The voltage range is 0 - 10 V. Beginning at 1V, each leak rate decade
is spread over 2 volts, i.e.:
Trigger level Output voltage (1 to 9V) will correspond to
3 g/a 0.1 to 100 g/a
0.2 oz/yr 0.01 to 10 oz/yr
5 x 10
-4
mbar l/s 1x10
-5
to 1x10
-1
mbar l/s