Fluke 28 II Ex User Manual

True-rms Digital Multimeter
How to Make Measurements
33
Duty Cycle Measurements
Duty cycle (or duty factor) is the percentage of time a
signal is above or below a trigger level in one cycle
(Figure 9). The duty cycle mode is optimized to measure
the on or off time of logic and switching signals. Systems
such as electronic fuel injection systems and switching
power supplies are controlled by pulses that have
different widths, which can be measured by a duty cycle
measurement.
To measure duty cycle, set up the Product to measure
frequency. Then push G a second time. As with the
frequency function, Push E to change the slope for
the counter.
For 5-V logic signals, use the 6-V dc range. For 12-V
switching signals in automobiles, use the 60 V dc range.
For sine waves, use the lowest range that does not result
in multiple triggers. (Normally, a distortion-free signal can
be up to ten times the amplitude of the selected voltage
range.)
If a duty cycle measurement is unstable, push MIN MAX;
then scroll to the AVG (average) display.
-Slope
Trigger Point
+Slope
Trigger Point
30% Above
+Slope
70% Below
-Slope
100%
iyf.eps
Figure 9. Components of Duty Cycle Measurements

Fluke 28 II Ex Specifications

General

Diode test	Yes
Product type	Digital multimeter
Product color	Black, Red
Frequency range	0.0005 - 199.99 kHz
DC current range	0.0000001 - 10 A
DC voltage range	0.0001 - 1000 V
Resistance range	0.1 - 50000000 Ω
Measuring category	CAT IV 600V
Placement supported	Handheld multimeter
Basic accuracy (frequency)	0.005%
Basic accuracy (DC current)	0.2%
Basic accuracy (DC voltage)	0.05%
Temperature measurement range	-200 - 1090 °C
Battery type	AAA
Power source	Battery
Battery technology	Alkaline
Number of batteries supported	3
Operating altitude	0 - 2000 m
Maximum storage altitude	10000 m
Operating relative humidity (H-H)	0 - 80 %

Weight and Dimensions

Depth	198.1 mm
Width	100 mm
Height	6.35 mm
Weight	698.5 g