Oxymat 7; Selection Of The Reference Gas; Reference Gases - Siemens SIPROCESS GA700 Operating Instructions Manual

9.2

OXYMAT 7

9.2.1

Selection of the reference gas

The various measuring spans must have at least one common value. This value is then
defined as the "physical zero point" and applies to all the measuring ranges. The reference
gas can be selected on the basis of the "physical zero point".
The following example with four measuring ranges illustrates this:
17 to 22% O
15 to 25% O
0 to 25% O
0 to 100% O
Exception: If the smallest measuring span is ≥ 5% O
amounts to no more than 16% O
range. The purity of the reference gas has to be appropriate for the measuring task.
9.2.2

Reference gases

Measuring range
0 to vol. % O
to 100 Vol. % O
(suppressed zero point with
measuring range end value
100 vol. % O
0 ≤ 21 ≤ 100% O
(suppressed zero with 21
vol. % O
Rack-mounted device
Operating Instructions, 01/2013, A5E31874006-01
The span of 17 to 22% O
2
point may lie within this range. Air (20.95% O
2
gas.
2
2
Recommended
reference gas
N
2 2
O
2 2
)
2
Air
2
within the span)
2
is part of all measuring ranges. The physical zero
2
and the distance to the reference gas
2
, the physical zero point can also lie outside the measuring
2
Reference gas
connection pressure
2000 to 4000 hPa above
sample gas pressure
(max. 5000 hPa absolute)
100 hPa with respect to
sample gas pressure
which may vary by a
maximum of 50 hPa
around the air pressure
Commissioning
9.2 OXYMAT 7
%) is suitable as the reference
2
Comment
The reference gas flow
is set automatically to
between
5 and 12 ml/min.
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