AMI Analyzer Manual
Glossary of Terms
••••
27
Process
Refers to the sample that is supposed to be analyzed. Typically an analyzer measures the product of a
chemical or physical process, and this is generally referred to as the "Process"
Range
The operational range of measurement of the analyzer. This is set by its amplifier sensitivity. Oxygen levels
higher than the range full-scale will not be measured accurately. Normally the analyzer should be measuring
oxygen concentrations between 20 and 80 percent of its range. In the case of the microprocessor based
2001/201 analyzers, normally refers to the range to which the analog output corresponds.
Response
The response time of an analyzer is defined as the time taken to go from the beginning of a noticeable change
to 90% of the final level. The beginning is often defined as 10% of the final level. This is also called the
"t90" time. The transit time of the gas is not included in this measurement.
RFI
Radio Frequency Interference. All analog circuits are prone to interference from high level radio frequencies,
and special precautions must be taken to prevent this. The quality of such design is referred to by the acronym
EMC, or electromagnetic compatibility - the property of being compatible with any practical electromagnetic
environment.
RS-232
“Recommended Standard (no.) 232” – a rather non-standard description of the simplest way of allowing two
computers or a computer and another device such as a printer, to talk to each other.
Span
To calibrate the upper end of the range of measurement, as opposed to the bottom end or zero. Generally this
is done by exposing the sensor to a gas of known concentration, and making the analyzer read that value.
Trace
Low levels of, in this case, oxygen. This term is used to describe unwanted levels of oxygen as a contaminant,
typically in the low ppm levels.
