Keithley 6485, Руководство пользователя

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Model 6485 and 6487 User’s Manual Relative, mX+b, m/X+b (reciprocal), and log 5-3
Programming example — relative
This program fragment establishes a 1
μ
A baseline for measurements:
CALC2:NULL:OFFS 1e-6 ' Set Rel value of 1
μ
A.
CALC2:NULL:STAT ON ' Enable Rel.
SYST:ZCH OFF ' Turn off zero check.
INIT ' Trigger reading.
CALC2:DATA? ' Request Rel’ed reading.
mX+b, m/X+b (reciprocal), and Logarithmic
mX+b and m/X+b
The following math operations manipulate normal display readings (X) mathematically
according to the following calculations:
Y = mX+b
Y = m/X+b
where: X is the normal display reading.
m and b are user-entered constants for scale factor and offset.
Y is the displayed result.
NOTE Changing the “m” or “b” for mX+b also changes it for m/X+b.
Logarithmic
This calculation converts input readings to logarithm base 10 values. The calculation is
performed as follows:
10X
log Y
=
where: X is the input reading.
Y is the logarithmic result.
For example: Assume that exactly 1mA is being measured by the Model 6485/6487.
1.000000mA
10
log 3 – =
NOTE This calculation uses the absolute value of the normal input reading as the log
of a negative number cannot be computed.