Teledyne 3010TA, Руководство по эксплуатации, Страница: 51 / 101

Oxygen Analyzer Part I: Control Unit
Part I: 4-19
The Model 3010TA 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
concentration exceeds the upper limit of the range, the DC output will
saturate at 1 V dc (20 mA at the current output).
However, the digital readout and the RS-232 output of the concentra-
tion are unaffected by the fixed range. They continue to read accurately with
full precision. See Front Panel description in chapter 1.
The automatic air calibration range is always 0-25 % and is not pro-
grammable.
4.6.1 Setting the Analog Output Ranges
To set the ranges, enter the range function mode by pressing the
Range
button on the front panel.
L—### M—####
H—##### Mode—AUTO
Use the < > arrow keys to blink the range to be set: low (
L
), medium
(
M
), or high (
H
).
Use the
∆∇
arrow keys to enter the upper value of the range (all ranges
begin at 0 ppm). Repeat for each range you want to set. Press
Enter
to
accept the values and return to
Analyze
mode. (See note below.)
Note: The ranges must be increasing from low to high, for example,
if range 1 is set as 0–100 ppm and range 2 is set as 0–1,000
ppm, range 3 cannot be set as 0–500 ppm since it is lower than
range 2.
Ranges, alarms, and spans are always set in ppm units (over the entire
0-250,000 ppm range), even though all concentration-data outputs change
from ppm units to percent when the concentration is above 10,000 ppm.
4.6.2 Fixed Range Analysis
The autoranging mode of the instrument can be overridden, forcing the
analyzer DC outputs to stay in a single predetermined range.