Modifications And Substitutions; Glossary - AMC -UT M-400 Series User Manual

AMC-UTx-M-xx-400 Series Digital Transmitter

1.5 MODIFICATIONS AND SUBSTITUTIONS

Due to an ongoing development program, AMC reserves the right to substitute components and
change specifications at any time without incurring any obligations.

1.6 GLOSSARY

Alarm
Calibration
Calibration Gas
DT
Gas Concentration
LEL
PPM
Percent by volume
Span
T90
T99
Zero Buffering
Zero Gas
Alarm is an audible, visual, or physical
presentation designed to warn the instrument user
that a specific level of a dangerous gas/vapor
concentration has been reached or exceeded.
Calibration is the procedure used to adjust the
instrument for proper response.
Calibration Gas is a gas of known
concentration(s) used to set the instrument span.
Catalytic needs air for calibration.
Digital Transmitter
Gas Concentration is measured in:
• PPM
• %LEL (Lower Explosive Limit)
Lower explosive limit is the lowest concentration
(percentage) of a gas or a vapor in air capable of
combusting in the presence of an ignition source
(arc, flame, heat).
Parts Per Million (1% volume = 10,000PPM)
Concentration of gas in a mixture expressed as a
percentage of total volume.
Full range of a sensor i.e. a CO sensor with a full
range of 0-100 PPM has a 100 PPM span.
Response Time in seconds to achieve 90% gas
concentration reading. This a typical calibration
point that allows for sensor aging, but tends to be
less accurate than a T99 calibration,
Response Time in seconds to achieve 99% gas
concentration reading. This is a more accurate
calibration point.
Zero buffering is transmitter function which
forces the gas concentration reading to zero when
sensor is exposed to low concentration of a gas.
The zero buffer is indicated in the sensor
specification.
Zero gas is gas in which the target gas is not
present. The presence of oxygen is required.
Clean air is an excellent source for zero
calibration. A known gas concentration can be
entered during zero calibration.
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