Teledyne 4020 - Hydrocarbon analyzer - Manual (Page 80)

Operation Model 4020
Teledyne Analytical Instruments 64
 Background Gas Selection
4.7.1 Zero Offset Adjustment
The software in this instrument provides a way to enter an offset to
the zero of the analyzer. This may be useful if, for example, the zero gas
is not pure and it contains some hydrocarbon. In this case, the reading
will have an offset that will be constant throughout its working range.
Thus, by entering an initial offset to the output (either current or
voltage), the display will match the output over the range of the
application.
Note: This adjustment only affects the % of range output of
Channel 1.
To access the offset function:
<▲▼> From the MAIN MENU, scroll to the ANALOG
ADJUST function using the UP/DOWN keys.
<Enter> Pressing <Enter> activates the function and takes you to
the next screen.
<Enter> Use the <Enter> key to move over to the Offset field.
<▲▼> Use the UP/DOWN keys to change each digits value.
<Enter> Use the <Enter> key to accept a digit and move to the
next character position. The final enter will accept the
value and move the arrow to the function which allows
you to set the gain.
Use the same procedure to set the gain of the instrument. After the
last digit is entered, the final <Enter> press will accept the gain value.
The value you enter for the offset to zero or gain will be
automatically added to the reading. Thus, if you entered -0.10 for zero
offset
, the display will show -0.10 for zero concentration.
During calibration, when the instrument enters the zero mode in
AUTO, the instrument will do the work of bringing the reading back to
zero plus the offset value that was entered. If you chose MANual zero