Fluke 5500A - Rms Versus Peak-To-Peak Waveforms

5500A
Operator Manual
4-16
!
60V
24V
MAX
OFFSET
ON/OFF
F/C
HOLD
K/J THERMOMETER
51
5500A
CALIBRATOR
20V PK
MAX
HI
LO
TC
TRIG
OUT
1000V
RMS
MAX
20V
RMS
MAX
1V PK
MAX
20V PK
MAX
NORMAL
AUX
SCOPE
V, ,
RTD
A, -SENSE,
AUX V
200V PK
MAX
Connection wiring must match thermocouple type, e.g., K, J, etc.
f4-10.eps
Figure 4-10. UUT Connection: Temperature (Thermocouple)
4-18. Rms Versus Peak-to-Peak Waveforms
The 5500A Calibrator ranges for ac functions are specified in rms (root-mean-square; the
effective value of the waveform). For example, 1.0 - 32.999 mV, 33 - 329.999 mV,
0.33 - 3.29999 V and so forth. The sinewave outputs are in rms, while the trianglewave,
squarewave, and truncated sinewave outputs are in peak-to-peak. The relationship
between peak-to-peak and rms for the non-sinewave types are as follows:
• Squarewave peak-to-peak x 0.5000000 = rms
• Trianglewave peak-to-peak x 0.2886751 = rms
• Truncated Sinewave peak-to-peak x 0.2165063 = rms
While the ac function ranges are directly compatible for sinewaves, the rms content of
the other waveforms is less apparent. This characteristic leads to subtle calibrator range
changes. For example, if you enter a sinewave voltage of 6 V (rms assumed), the
selected range is 3.3 to 32.9999 V. If you then use the softkeys to change from a
sinewave to a trianglewave, for example, the display changes from 6 V rms to 6 V peak-
to-peak. This translates to 6 V peak-to-peak x 0.2886751 = 1.73205 V rms, and the range
switches to 0.33 to 3.29999 V. The Output Display shows the range change because the
sinewave voltage is displayed as 6.0000, the resolution for the 3.3 to 32.9999 V range,
while the trianglewave is displayed as 6.00000, the resolution for the 0.33 to 3.29999 V
range.
You need to know the active range to enter the correct values for voltage offset because
the maximum offsets are range specific. For example, the maximum peak signal for the
3.3 to 32.9999 V range is 55 V while the maximum peak signal for the 0.33 to 3.29999 V
range is 8 V. This means in the example above, the 6 V rms sinewave could have offsets
applied up to the maximum peak signal of 55 V because the active range is 3.3 to
32.9999 V, while the 6 V peak-to-peak trianglewave could have offsets applied up to the
maximum peak signal of 8 V because the active range is 0.93 to 9.29999 V. See
“Specifications” in Chapter 1 and “Entering a DC Offset” later in this chapter for more
information about dc offset voltages.