4 Operation

Model 3020T

 

 

 

 

 

 

 

 

 

Although the instrument can be spanned using air, a span gas with a known oxygen concentration in the range of 70–90% of full scale of the range of interest is recommended. Since the oxygen concentration in air is 209,000 ppm, the cell can take a long time to recover if the instrument is used for trace oxygen analysis immediately following calibration in air.

Connect the calibration gases to the analyzer according to the instruc- tions given in section 3.5, Gas Connections, observing all the prescribed precautions.

Shut off the gas pressure before connecting it to the analyzer, and be sure to limit the pressure to 40 psig or less when turning it back on.

Readjust the gas pressure into the analyzer until the flowrate (as read on the analyzer’s SLPM flowmeter) settles between 0.5 and 2.4 SLPM (ap- proximately 1-5 scfh).

If you are using password protection, you will need to enter your

password to gain access to either of these functions. Follow the instructions in section 4.4 to enter your password. Once you have gained clearance to proceed, you can ENTER the ZERO or SPAN function.

4.8.1 Zero Cal

The ZERO function on the MAIN MENU is used to enter the zero calibration function. Zero calibration can be performed in either the auto- matic or manual mode. In the automatic mode, an internal algorithm com- pares consecutive readings from the sensor to determine when the output is within the acceptable range for zero. In the manual mode, the operator determines when the reading is within the acceptable range for zero.

Make sure the zero gas is connected to the instrument.

If you get a CELL FAILURE message skip to section 4.8.1.3.

4.8.1.1Auto Mode Zeroing

Select ZERO to enter the ZERO function. The ZERO screen allows you to select whether the zero calibration is to be performed automatically or manually. Use the DOWN/UP control to toggle between AUTO and MAN zero settling. Stop when AUTO appears on the display.

Zero: Settling: AUTO

<ENT> To Begin

ENTER to begin zeroing.

####

PPM

Zero

Slope=####

 

ppm/s

4-10

Teledyne Analytical Instruments

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Image 46
Teledyne 3020T operating instructions Zero Cal, Auto Mode Zeroing