Operator`s manual

Figure 4-1. Make Voltage ACV measurements with the source ground attached to the SM2060 V,Ω - to
minimize “Common Mode” measurement problems.
2064)
Mea a repetitive waveform between 30 Hz
g
t of
ting the comparator threshold level for best counter sensitivity and noise immunity. (It is difficult to
ea at the comparator input
due t the comparator
his function requires a repetitive signal. The DMM must be in AC voltage measurement mode, with the
4.1.3 AC Peak-to-Peak and Crest Factor (SM
surement of Peak-to-Peak, Crest Factor and AC Median values requires
and 100 kHz. The DMM must be in AC voltage measurement mode, with the appropriate range selected. Knowin
the Peak-to-Peak value of the waveform is useful for setting the Threshold DAC (described below). This latter
function is a composite function, and may take over 10 seconds to perform.
4.1.4 AC Median Value Measurement (SM2064)
To better understand the usage of this function, you should note that the DMM makes all AC voltage measurements
through an internal DC blocking capacitor. The voltage is thus “AC coupled” to the DMM. The measuremen
the Median value of the AC voltage is a DC measurement performed on the AC coupled input signal. This
measurement returns the mid-point between the positive and negative peak of the waveform. The Median value is
sed for setu
m sure the frequency of a low duty cycle, low amplitude AC signals since there is DC shift
o the internal AC coupling. The SM2064 overcome this problem by allowing you to set
threshold level). For further information on the usage of AC Median value and Peak-to-Peak measurements, and
the Threshold DAC, see the “Frequency and Timing Measurements” section below.
T
appropriate range selected.
4.2 Current Measurements
The SM2060 measures AC and DC currents between 100 ηA and 2.5 A. Use the +I, 4WΩ terminals, being certain
to always leave the V,Ω + & - terminals disconnected. Use the AC/DC button to switch between AC and DC. Th
C current is an AC coupled True R
e
MS measurement function. See figure 4-2 for connection.
The . The 2.4mA and 24mA ranges utilize a 10Ω shunt,
A
Current functions are protected with a 2.5 A, 250 V fuse
while the 240mA and 2.4A ranges use a 0.1Ω shunt. In addition to the shunt resistors, there is some additional
parasitic resistance in the current measurement path associated with the fuse and the internal wiring. The result is a
burden voltage of up to about 250mV.
33 Signametrics