Teledyne BDS-3960 operating instructions Range Function, Setting the Analog Output Ranges

Oxygen Analyzer Maintenance

4.6The Range Function

The Range function allows the operator to program up to four concentration ranges to correlate with the DC analog outputs. If no ranges are defined by the user, the instrument defaults to:

Range 1 = 0–100 ppb

Range 2 = 0–1000 ppb

Range 3 = 0–10000 ppb

Range 4 = 0–100000 ppb

The Model BDS 3960 is set at the factory to default to autoranging. In this mode, the PPC application 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 90% 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 VDC (20 mA at the current output).

Even if the output is set to a fixed range, the digital readout of the concentration is unaffected by the fixed range. It continues to read accurately with full precision. See Front Panel description in Chapter 1.

The automatic fourth range is always 0-100000 ppb (100 ppm) and should not be adjusted.

4.6.1Setting the Analog Output Ranges

To set the ranges, click on the list box on the main screen. The following options will pop down.

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