Keithley 2790, Reference Manual

Page: 285 / 568

10-2 Model 2790 SourceMeter
®
Switch System Reference Manual
Operation enhancements
There are some operations you can do over the IEEE-488 bus and RS-232 interface that
you cannot do from the front panel. The more important ones are summarized below.
Pseudocards
Using remote operation, you can assign a pseudocard to an empty switching module slot.
With a pseudocard installed, the Model 2790 will operate as if the switching module is
installed in the Model 2790. This feature allows you to configure your system without
having the actual switching module installed in the unit. There is a pseudocard for the
7751, 7752, 7753, and 7702 switching modules.
A single SCPI command (SYSTem:PCARdX, where X=1 or 2) is used to install a
pseudocard in an empty switching module slot. Details are provided in
Section 2 .
A pseudocard cannot be installed from the front panel. However, once it is installed, you
can take the Model 2790 out of remote and use the front panel. When the instrument is
turned off, the pseudocard will be lost (uninstalled).
Autozero
Autozero is part of the normal measurement process to assure stable, accurate measure-
ments. Autozero can be disabled to increase measurement speed. However, the readings
will eventually become inaccurate over time and temperature changes.
Autozero can only be disabled using remote programming. It cannot be disabled from the
front panel. Autozero is covered in
Section 3 .
dB calculation
Using remote programming, you can select the dB calculation for DC or AC voltage. The
dB calculation makes it possible to compress a large range of measurements into a much
smaller scope. See
Section 5 to select and configure the dB calculation.
You cannot select dB from the front panel. However, once it is selected you can take the
Model 2790 out of remote and use the front panel. When the instrument is reset to default
conditions (or turned off), dB will be lost.
Separate function setups
A few settings from the front panel are global. That is, the setting on one function also
applies to the other functions. For example, if you set DCV for 3 digits, all the other func-
tions will also be set to 3 digits. Using remote programming, each function can have its
own unique setup. For example, DCV can be set to 3 digits, ACI can be set to 4
digits, and DCI can be set to 5 digits.