Trace Oxygen Analyzer Operation 4
4-19
Teledyne Analytical Instruments
• Defeated? Dft–Y/N (Yes/No)
• Failsafe? Fs–Y/N (Yes/No)
• Latching? Ltch–Y/N (Yes/No).
• To define the setpoint, use the < > arrow keys to move the
blinking over to AL–1 ####. Then use the Δ∇ arrow keys to
change the number. Holding down the key speeds up the
incrementing or decrementing. (Remember, the setpoint units are
ppm O2.)
• To set the other parameters use the < > arrow keys to move the
blinking over to the desired parameter. Then use the Δ∇ arrow
keys to change the parameter.
• Once the parameters for alarm 1 have been set, press Alarms
again, and repeat this procedure for alarm 2 (AL–2).
• To reset a latched alarm, go to Dft– and then press either Δ two
times or ∇ two times. (Toggle it to Y and then back to N.)
–OR –
Go to Ltch– and then press either Δ two times or ∇ two times.
(Toggle it to N and back to Y.)
4.7 The Range Function
The Range function allows the operator to program up to three concen-
tration ranges to correlate with the DC analog outputs. If no ranges are
defined by the user, the instrument defaults to:
Low = 0–1 ppm
Med = 0–10 ppm
High = 0–100 ppm.
The Model 3000TA-XL is set at the factory to default to autoranging.
In this mode, the microprocessor automatically responds to concentration
changes by switching ranges for optimum readout sensitivity. If the current
range limits are exceeded, the instrument will automatically shift to the next
higher range. If the concentration falls to below 85% of full scale of the next
lower range, the instrument will switch to that range. A corresponding shift
in the DC percent-of-range output, and in the range ID outputs, will be
noticed.
The autoranging feature can be overridden so that analog output stays
on a fixed range regardless of the oxygen concentration detected. If the