Fluke 5720A 3140 A14/A15/A16 2.2A AC Range Abs. Value, 3141 A14/A15/A16 2.2A DC Range Dummy Load

5700A/5720A Series II Calibrator

Service Manual

3140 A14/A15/A16: 2.2A AC Range Abs. Value

The instrument is configured to the ac 2.2A range and set for an output current of 0.22A at 1 kHz, 0.6A at 1 kHz, 1.1A at 1 kHz, 0.6A at 40 Hz, and 1.1A at 50 Hz. The output current from the High Voltage/High Current assembly is routed to the Current assembly where it is connected to the 1.2Ω load resistor. The Current control signal G OUT from the High Voltage/High Current assembly is routed to the Absolute Value Circuit on the High Voltage Control. The output from the Absolute Value circuit is a positive voltage which should be = 3.07 * I, ±10%, where "I" is the output current. This voltage is divided creating MUX6 which is connected to the SDL line where it is measured by the adc circuit on the DAC assembly.

3141 A14/A15/A16: 2.2A DC Range Dummy Load

The instrument is configured to the dc 2.2A range. The output current from the High Voltage/High Current assembly is routed to the Current assembly where it is connected to the 1.2Ω load resistor. The resulting voltage across this load resistor is measured by connected DUMMY LOAD on the Current assembly to the SDL line where it is measured by the adc circuit on the DAC assembly. This fault occurs if the determined current is over 10% ±5 mA of the nominal. A failure indicates the High Voltage/High Current assembly (A15) is probably at fault.

3142 A14/A15/A16: 2.2A DC Range Compliance

The instrument is configured to the dc 2.2A range. The output current from the High Voltage/High Current assembly is routed to the Current assembly where it is connected to the 1.2Ω load resistor. The compliance voltage is determined by measuring the output side of the 22 mA range shunt resistor on the Current assembly. This is done via the Current Compliance Monitor circuit on the Current assembly and is checked to be less than 10V. A failure indicates the High Voltage/High Current assembly is probably at fault.

3143 A14/A15/A16: 2.2A DC Range Magnitude

The instrument is configured to the dc 2.2A range. The output current from the High Voltage/High Current assembly is routed to the Current assembly where it is connected to the 1.2Ω load resistor. The output current is calculated by measuring the voltage drop across the 22 mA range shunt resistor on the Current assembly. This fault occurs if the determined current is over 10% of the nominal. A failure indicates the High Voltage/High Current assembly (A15) is probably at fault.

3300 A9: 8255 Control Word

The diagnostics software reads the control word of the 8255 IC on the Ohms Cal assembly (A9). A failure indicates the Ohms Cal assembly (A9) is probably at fault.

3301 A9: 8255 Port a Fault

The diagnostics software writes and reads data to port A of the 8255 IC on the Ohms Cal assembly (A9). A failure indicates the Ohms Cal assembly (A9) is probably at fault.

3302 A9: 8255 Port B Fault

The diagnostics software reads port B of the 8255 IC on the Ohms Cal assembly (A9) during the instruments dormant state. A failure indicates the Ohms Cal assembly (A9) is probably at fault.

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