Agilent Technologies 34970A, Руководство пользователя

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137
Chapter 4 Features and Functions
Mx+B Scaling
4
• You can make a null measurement on a channel and store it as the
offset (“B”) for subsequent measurements. This allows you to adjust
for voltage or resistive offsets through your wiring to the point of the
measurement.
• During a Monitor operation, the gain and offset values are applied to
all readings on the specified channel.
• You can specify a custom label with up to three characters. You can
use letters (A-Z), numbers (0-9), an underscore ( _ ), or the “#”
character which displays a degree symbol ( ° ) on the front panel
(displayed as a blank space in an output string from the remote
interface). The first character must be a letter or the “#” character
(the “#” character is allowed only as the leftmost character in the
label). The remaining two characters can be letters, numbers, or an
underscore.
Note : If you set the measurement label to °C, °F, or K, note that this
has no effect on the temperature units set in the Measure menu.
• Although the instrument does not directly support strain gage
measurements, you can measure a strain gage using a 4-wire
resistance measurement with scaling.
For more information, refer to
“Strain Gage Measurements” on page 295.
Note : Agilent BenchLink Data Logger 3 software has built-in strain
gage measurement capability.
Use the following equations to calculate the gain and offset.
M =
B =
Where GF is the gage factor and R
0
is the unstrained gage resistance.
For example, a 350  strain gage with a gage factor of 2 would use the
following gain and offset values: M=0.001428571, B=-0.5 (be sure to
use 6½ digits of resolution for this measurement).
1
GF R
0

----------------------
1
GF
-------- –
34970A Refresh UG.book Page 137 Wednesday, February 17, 2010 12:34 PM