Teledyne 3160 - Manual (Page 31)

Operations 4 Operations 4 Operations 4 Operations 4 Operations 4
4-3 TELEDYNE ANALYTICAL INSTRUMENTS
When waiting for manual sensor settling during calibration zeroing, wait
until the oxygen concentration has reached its lowest value and has remained
so for 10–15 minutes. It is important to make sure that the sensor is reading the
lowest possible value, since zeroing will reset the point at which the sensor
reads zero. Do not zero prior to reaching the lowest possible oxygen concentra-
tion. When initially installing the sensor(s), do a zero calibration, then a span
calibration. If desired, the instrument may be programmed for automatic
periodic zeroing (AutoZeroing) if the optional scrubber is installed. AutoZero-
ing uses the scrubber to generate a zero gas from a low O
2
sample gas.
NOTE: 1. Zeroing in the 0-1 PPM range preserves the life of the scrubber.
In scheduled zeroing and spanning (AutoZeroing and AutoSpanning), a
time interval must be chosen. This interval determines how often the instru-
ment zeros or spans itself. To change the scheduled time, edit it after setting
the interval in the Set Up Clock Functions mode.
NOTE: 2. AutoZeroing and AutoSpanning may be delayed until the alarms have been
enabled.
Calibration Using Span Gas: After zeroing, the instrument can now
be calibrated using a span gas with a known oxygen concentration. The analyz-
er may be calibrated on any range other than 0–1 PPM, but it is best to cali-
brate one range up from the range where the sample is expected to be. The
span gas concentration should be within 70% to 99% of full scale of the range
selected.
NOTE: 3. Prior to calibration, allow the analyzer reading to come to a stable value with
zero or sample gas flowing through the analyzer.
Select Active Sensor (Two cell blocks only): One or two O
2
sensor
blocks can be installed in the system. In dual sensor systems, either sensor can
be isolated with pneumatic valves, and the other sensor chosen as the active
sensor for O
2
measurements. The system software is aware of how many
sensor blocks are present, but will not automatically switch sensors should one
fail.
This menu will not appear if only one cell block is installed.
Install Sensor and Test Alternate Sensor (Two cell blocks only): Pro-
cedures are provided for installing a new sensor and for testing the alternate O
2
sensor.
This menu will not appear if only one cell block is installed.
O
2
Range Set-Up: The measurement range may be manually chosen, or
the system may be set to automatically choose the range (AutoRanging). In the
AutoRanging mode, the range will step up at greater than 100% and step
down at 80% of full scale of the current range. The analyzer is programmed to
prevent oscillation between ranges during rapidly changing oxygen levels.