Db Commands - Keithley 3700 series Reference Manual

Series 3700 System Switch/Multimeter Reference Manual
The displayed units designator for reciprocal readings is ―R.‖ This units designator cannot be
changed.
Example: Assume the normal displayed reading is 002.5000Ω. The reciprocal of resistance is
conductance. When the reciprocal math function is enabled, the following conductance reading
will be displayed:
0.400000 R
NOTE
Basic operation
1. Configure and enable the mX+b, percent, or reciprocal (1/X) math function as previously
explained.
2. Select the desired measurement function.
3. Apply the signal to be measured to a switching channel input.
4. Close the input channel. The result of the math calculation will be displayed when a reading
is triggered.
Scanning
When a scan is configured, each channel can have its own unique math setup. For remote
programming, the <ch_list> parameter is used to configure channels for a scan.
For example:
To attach math settings (like dmm.math.enable, dmm.math.percent, etc.) to a desired
configuration, send the following commands:
dmm.configure.set("myconfig")
dmm.setconfig("1001, 1003", "myconfig")
Once a configuration like "myconfig" is tied to a channel that channel may be added to scan list
with a scan.add command.

dB commands

Expressing DC or AC voltage in dB makes it possible to compress a large range of
measurements into a much smaller scope. The relationship between dB and voltage is defined
by the following equation:
Document Number: 3700S-901-01 Rev. A / August 2007
The result of the 1/X calculation may be displayed in exponential notation. For
example, a displayed reading of +2.500E+03 R is equivalent to 2500 R (2.5K R).
When using REL, the REL'ed reading of the input signal is used by the 1/X calculation.
Section 5: Relative, Math, and dB
5-7