Teledyne 3020M - Explosion proof paramagnetic oxygen analyzer User Manual

Page 51

Percent Paramagnetic Oxygen Analyzer

Operation 4

4-15

Teledyne Analytical Instruments

number. Holding the control on the DOWN or UP position, while
the number changes, speeds up the incrementing or
decrementing. (Remember, the setpoint units are always % O

•

To set the other parameters use ENTER to blink the desired
parameter. Then use DOWN/UP to change the parameter.

•

Once the parameters for the alarm have been set, ENTER the

ALARM

function again, and repeat this procedure for next alarm.

•

To reset a latched alarm:

Go to

Dft–

and then assert either DOWN two times or UP two

times. (Toggle it to

and then back to

)

–OR –

Go to

Ltch–

and then assert either DOWN two times or UP two

times. (Toggle it to

and back to

)

Note: In this screen, ENTER moves you through the fields and

ESCAPE takes you back to the previous screen.

4.11 The RANGE Function

The

RANGE

function allows the operator to program up to three

concentration ranges to correlate with the DC analog outputs. If no ranges
are defined by the user, the instrument defaults to:

Low = 0–5 %

Med = 0–25 %

High = 0–100%.

The Model 3020M 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 sample concentration falls below the 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 VDC or 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.