35040

Operators Manual

Figure 3-8 shows the ion chamber bias voltage (IC Bias), the system leakage current (Leakage), and the battery voltage and current. The bias voltage shown is 300.0 volts. The central electrode is positive (CEP). The leakage current is 0.001 picoamps. The battery current is a small positive number, thus the battery is charging and is almost fully charged.

ADC

Batt: 6.8 V +0.10 A

Leakage: 0.001 pA

IC Bias: 300.0 V CEP

Figure 3-8. The Test Function Screen 2 - Bias, Leakage, and Battery Voltage and Current

The battery current (shown in Figure 3-8), “+0.1 A”, is displayed to the right of the battery voltage, “6.8 V”. A positive current value of up to 2.5 amperes indicates that the battery is being charged from the AC line. As the battery approaches full charge, the current will decrease to near zero. A negative current value will be shown when the instrument is operated from battery power. A negative current indicates the actual current consumption of the instrument.

During a charging cycle, the battery voltage can range from 5.5 volts to 8.5 volts. After the battery reaches its full charge, the charging circuit switches to float charge stage with a corresponding voltage of approximately 7 volts. The unit will remain in the float charge stage as long as the instrument is attached to an AC line. When the instrument is operated from battery power, the voltage will read between 6.5 volts (battery fully charged) and 5.4 volts (low battery shutdown voltage).

The two scale factors that appear in Figure 3-9 are those determined by a calibration agency. QScaleFactor adjusts the charge. IScaleFactor adjusts the current. See Section 2.3 for details.

ADC

QScaleFactor=1.0000

IScaleFactor=1.0000

Figure 3-9. The Test Function Screen 3 - Calibration Scale Factors

Figure 3-10 shows the present settings for the start and stop threshold currents and the instantaneous current measurement. See Section 3.9.5 for details.

ADC

Start Thres: 1.0pA

Stop Thres: 0.9pA

Current: 0.0pA

Figure 3-10. The Test Function Screen 4 - Leakage Threshold Screen

Figure 3-11 shows the automatic leakage compensation settings, which consist of the ALC status, start and stop threshold currents, and the instantaneous current measurement. Refer to Section 3.9.5 for details.

3-10

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Fluke 35040 manual QScaleFactor=1.0000 IScaleFactor=1.0000