INFICON Ecotec E3000 Multigas-Sniffer-Leak Detector Interface description - Manual (Page 11)

2 I/O Port
11
In
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Ecotec E300
0,
k
ins
22e1
-j
, 1401
1.0 … < 3 V: 1
st
decade

3.0 … < 5 V: 2
nd
decade

5.0 … < 7 V: 3 rd decade

7.0 … < 9 V: 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 V).
:
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).
Default setting: logarithmic
LOG The voltage range spans from 0 V to 10 V. Beginning at 1 V, each leak rate
decade is spread over 2 V, i.e.:
Table 3: Example, Trigger level and output voltage
Trigger level Output voltage (1 … 9 V) will correspond to
3 g/a 0.1 … 1000 g/a
0.2 oz/yr 0.01 … 100 oz/yr
5
10 -4
mbar l/s 1
10 -5
… 1
10 -1
mbar l/s
Table 4: Trigger level, leak rate and output voltage
Trigger Leak rate Output voltage
0.1 oz/yr 1.5 oz/yr
 5.35 V
3 g/a 20 g/a
5.60 V
50 g/a
6.39 V
5
10 -4
mbar l/s 8
10 -5
mbar l/s
2.806 V
6
10 -3
mbar l/s
6.556 V