Model 755A
Instruction Manual
a.Zero Calibration Gas
b.Downscale Standard Gas
Digital Display - Typically, although not necessarily, the downscale standard gas will be
Recorder Readout - The downscale standard gas is selected to establish a calibration point at or near the lower range limit.
c.Upscale Standard Gas
Digital Display - Typically, the upscale standard gas will be a readily obtained gas such as dry air (20.93% oxygen) or 1005 oxygen.
Recorder Readout - A suitable upscale standard gas is required to establish a calibration point at or near the upper range limit. If this range limit is 21% or somewhat above 21%, the usual standard gas is dry air (20.93% oxygen).
CAUTION
PRESSURE LIMIT
Under no circumstances allow pressure to exceed 10 psig (69 kPa) as irreparable damage to the detector may result.
Many different sample handling systems are available, depending on the requirements of the individual user. Most sample handling systems have copper or brass components; however, stainless steel components are
available for applications involving corrosive gases. With corrosive gases, complete drying of the sample is desirable, as most of these gases are practically inert when totally dry.
For specific corrosive applications, consult the factory.
a.Sample Temperature Requirements
Sample temperature at the analyzer inlet should be in the range of 50°V to 150°F (10°C to 66°C). With a thoroughly dry sample, entry temperature can be as high as 150°F (66°C) without affecting readout accuracy. Normally, a maximum entry temperature of 110°F (43°C) is recommended so that the sample temperature will rise during passage of the sample through the analyzer. This precaution ensures against cooling of the sample and possible condensation of moisture. Such condensation should be avoided as it may damage the detector.
b.Sample Pressure Requirements: General
Operating pressure limits are the following: maximum, 10 psig (69 kPa gauge pressure); minimum,
CAUTION
OPERATING LIMITS
Operation outside the specified limits may damage the detector and will void the warranty.
Oxygen readout is automatically corrected for atmospheric pressure variations within
±3% of the target value, which may be set anywhere within the range of
The basic rule for pressure of sample and standard gases supplied to the inlet is to calibrate the analyzer at the same pressure that will be used during subsequent operation and to maintain this
Rosemount Analytical Inc. A Division of Emerson Process Management | Installation |