Measure Dc Voltage; Simple Lead Connections - Fluke 8588A Operator's Manual

When you select Manual, use the softkeys and the numerical keypad to edit the
integration time by PLC and Time. The smallest time aperture is 0 seconds with
200 ns increments and has an upper time limit of 10 seconds.
PLC refers to Power Line Cycles. A PLC at a 50 Hz line is 20 ms; a PLC at a
60 Hz line is 16.67 ms. The smallest aperture that can be set by PLC is 0.01. The
upper limit is the PLC equivalent of 10 seconds so is determined by the line
frequency setting in the Instrument Setup menu. For a 50 Hz line setting, the
maximum is 500 PLC, for a 60 Hz setting it is 600 PLC.
When the aperture is set by time, the display shows the nearest equivalent PLC
to 0.01 PLC precision. When the aperture is set by PLC, the display shows the
aperture in seconds with 200 ns resolution.
Use the navigation keys and  to choose the aperture setting method. The
aperture settings for Auto and Auto Fast for different resolution settings are
shown in Table 8.

Measure DC Voltage

The sections below explain how to accurately measure dc voltage.

Simple Lead Connections

For the majority of applications, the simple lead connection without external
guard is adequate as in Figure 2. Use and then  (Ext. Guard OFF).
See Input Terminal Selection (INPUTS). The disadvantage of this arrangement is
that the lead connection can form a loop. If a stray alternating magnetic field
(from the line transformer of a neighboring instrument, for example) passes
through the loop, it behaves as a single-turn secondary winding inducing
unwanted ac voltages into the measuring circuit. Use a twisted-pair to reduce the
loop area and adjacent twists will cancel any induced voltages. If you encounter
problems with stray pick-up, Fluke Calibration recommends that you use a
shielded twisted-pair cable with the screen connected to the INPUT LO terminal
at the source as shown in Figure 3.
Figure 2. Simple Lead Connections
Figure 3. Twisted-Pair Cable Connections
Reference Multimeter and 8 ½ Digit Multimeter
Functions
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