Teledyne 300M - Manual (Page 49)

Teledyne API Model 300M CO Analyzer Instruction Manual, 04033, Rev. A
4.6 Setting the CO Concentration Range
The CO concentration range is the concentration value that corresponds to the maximum voltage
output at the rear panel (usually 5 volts). The M300M can operate in one of three analog output
Range Modes. The Range Mode can be changed through the SETUP-RNGE-MODE menu. The
modes are described below.
4.6.1 Single Range Mode (SNGL)
In this mode, both analog outputs (REC and DAS) are set to the same range. This range can be
set to any value between 1 and 20,000 PPM and is accessed through the SETUP-RNGE-SET
menu. This is the default range mode for the analyzer.
4.6.2 Dual Range Mode (DUAL)
Selecting dual range mode will allow you to select different ranges for the REC and DAS analog
outputs. The two ranges are called Low and High. The REC output at the rear panel is used for
the Low range and the DAS output is used for the High range. To set the ranges press SETUP-
RNGE-SET and select which range you want to edit followed by ENTR.
The High and Low ranges have separate slopes and offsets for computing the Carbon Monoxide
concentration. Therefore, the two ranges must be independently calibrated. See Section 3.1.3 for
details on calibrating the two ranges.
4.6.3 Auto Range Mode (AUTO)
In auto range mode, the analyzer automatically switches between the Low and High range
depending on the concentration. When the CO concentration increases to 98% of the Low range
value, the analyzer will switch to the High range. The analyzer will remain in the High range
until the CO concentration drops to 75% of the Low range value. It will then switch back to the
Low range. Auto ranging changes the range for the REC and DAS outputs simultaneously. To
set the ranges press SETUP-RNGE-SET and select which range you want to edit followed by
ENTR.
The High and Low ranges have separate slopes and offsets for computing the Carbon Monoxide
concentration. Therefore, the two ranges must be independently calibrated. See Section 3.1.3 for
details on calibrating the two ranges.
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