Teledyne GFC-7000E - Trace CO2 Analyzer - Manual (Page 72)

Model GFC7000E Instruction Manual Operating Instructions
04584 Rev A1 61
6.7.5. Auto Range Mode (AUTO)
In AUTO range mode, the analyzer automatically switches the reporting range between two user-
defined ranges (low and high). The unit will switch from low range to high range when the CO
2
concentration exceeds 98% of the low range span. The unit will return from high range back to
low range once both the CO
2
concentration falls below 75% of the low range span.
In AUTO Range mode the instrument reports the same data in the same range on both the A1
and A2 outputs and automatically switches both outputs between ranges as described above.
Also, the RANGE test function displayed on the front panel will automatically switch to show
which range is in effect.
The high/low range status is also reported through the external, digital status bits (Section
6.13.1.1).
To set individual ranges press the following keystroke sequence.
SAMPLE* RANGE = 500.000 PPM CO2 =X.XXX
< TST TST > CAL SETUP
SETUP X.X PRIMARY SETUP MENU
CFG DAS RNGE PASS CLK MORE EXIT
SETUP X.X RANGE CONTROL MENU
MODE SET UNIT EXIT
SETUP X.X RANGE MODE: SNGL
SNGL DUAL AUTO ENTR EXIT
SAMPLE ENTER SETUP PASS : 818
8 1 8 ENTR EXIT
EXIT x 2 returns
to the main
SAMPLE display
SETUP X.X RANGE MODE: AUTO
SNGL DUAL AUTO ENTR EXIT
SETUP X.X RANGE CONTROL MENU
MODE SET UNIT EXIT
SETUP X.X HIGH RANGE: 500.0 Conc
0 0 5 0 0 .0 ENTR EXIT
SETUP X.X LOW RANGE: 500.0 Conc
0 0 5 0 0 .0 ENTR EXIT
Toggle the numeral
keys to set the
LOW and HIGH
range value.
ENTR accepts the
new setting, EXIT
ignores the new
setting.
CAUTION
In AUTO range mode the LOW and HIGH ranges have separate slopes and offsets for
computing CO2 concentration.
The two ranges must be independently calibrated.
NOTE
Avoid accidentally setting the low range of the instrument with a higher span limit than
the high range. This will cause the unit to stay in the low reporting range perpetually
and defeat the function of the AUTO range mode.