Teledyne 7300A manual Auto Screen

4 Operation Model 7300A

Note: If all three ranges are currently defined for different applica- tion gases, then the above screen does not display (because mode must be manual). Instead, the VFD goes directly to the following screen.

If above screen displays, use the UP/DOWN arrow keys to Select MANU- AL, and press Enter.

Select range to run —> Ø1 Ø2 Ø3 CAL<—

Use the UP/DOWN keys to select the range: 01, 02, 03, or CAL. Then press Enter.

Gas use: CO2

Range: Ø — 10 %

Use the ENTER key to move the range to low-end field. Use ENTER key to move the range to high-end field. Use the UP/DOWN keys to change the values of the fields.

Press Escape to return to the previous screen to select or define another range.

Press Enter to return the to the Analyze function.

4.6.2 Auto Screen

Autoranging will automatically set to the application that has at least two range setup with the same gases.

In the autoranging mode, the microprocessor automatically responds to concentration changes by switching ranges for optimum readout sensitivity. If the upper limit of the operating range is reached, the instrument automatically shifts to the next higher range. If the concentration falls to below 85% of full scale of the next lower range, the instrument switches to the lower range. A correspond- ing shift in the DC concentration 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 contaminant concentration detected. If the concen- tration 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 concentration are unaffected by the fixed range. They continue to read beyond the full-scale setting until amplifier saturation is reached. Below amplifier saturation, the over

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