Emerson 755A Manuel D’Utilisation

245364-V

May 2002

Rosemount Analytical Inc.    A Division of Emerson Process Management                                                                         Operation     3-5

Model 755A

2.  A zero-suppressed range uses a

blend consisting of a suitable
percentage of oxygen contained in a
background gas, typically nitrogen.

The upscale standard gas is required to
establish a calibration point at or near the
upper range limit.  For example, if this

range limit is 21% (or somewhat greater
than 21%), the usual upscale standard
gas is dry air (20.93% oxygen).

Typical examples of standard gases for
recorder oxygen ranges are shown in
Table 3-2, page 3-6.

0 to 1

Nitrogen

0.9% O2

Balance N2

0 to 10

Nitrogen

9% O2

Balance N2

0 to 100

Nitrogen

100% O2

20 to 21

20.2% 

±0.2% O2

Air (20.93% O2)

11 to 21

11.2% 

±0.2% O2 Balance N2

Air (20.93% O2)

99 to 100

High Purity O2 with 0.8% 

±0.05% High Purity N2

High Purity O2

90 to 100

91% 

±0.5% O2 Balance N2

High Purity O2