Teledyne Model 300EU Auto-Reference Mode Aref, Mode Field, M300EU, AUTO-REF RANGE = 50.000 PPM

M300EU	M300EU OPERATING INSTRUCTIONS
(Addendum to M300EU Manual - P/N 04145)

6.2.1. AUTO-REFERENCE MODE (AREF)

One of the most significant differences between the M300E/EM and the M300EU analyzers is the auto-reference measurement feature. In this mode, the analyzer makes special measurements and calculations that are applied to the CO concentration calculation to dramatically improve interferent rejection as well as compensate t for changes in ambient temperature of the sample gas and age related drift of the optical bench components (see Section 10.1.1 for detailed information about how and when this A-REFfeature occurs).

When in A-REFmode, the analyzer:

•Freezes the CO concentration reading displayed on the front panel and output via the analog outputs or COM Ports.

•Displays the Message AUTO-REFin the mode filed of the analyzer’s front panel.

•Sets the A-REFstatus output (pin-7 on the status output connector) to high.

Mode Field

AUTO-REF RANGE = 50.000 PPM	CO =12.430
<TST TST> CAL CALZ CALS		SETUP

Figure 6-1: Typical Front Panel Display during A-REF Mode

NOTE:

Initiating a calibration through either the keyboard, the COMM ports or digital control inputs terminates

the A-REF mode.

Also, when the instrument is in calibration mode, the A-REF mode is suppressed until the instrument

exits calibration mode.

See Section 6.4 for information about changing the A-REFcycle time or manually initiating an auto-reference measurement.

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