User manual

2400 Series SourceMeter

User’s Manual Connections 2-13

Guard selection

Cable guard is used for high-impedance guarding for cables (i.e., coax and triax)

and test fixtures. Ohms guard provides a high-current guard output, which allows

in-circuit guarded ohms measurements. On power-up, cable guard is selected.

NOTE For 6-wire ohms measurements, use the guard output off mode. See

Section 13, “Front panel output configuration,” for details on the various

output off states and how to select the guard output off state. See also

Section 4, “6-wire ohms measurements.”

Front panel guard selection

Perform the following steps to check or change the guard selection:

1. Press CONFIG and then SOURCE V, SOURCE I, or Ω. Changing guard in

one configuration menu changes it in all of the others.

2. Using the SOURCE arrow keys, place the cursor (flashing menu item) on

GUARD and press ENTER.

NOTE Cursor position indicates the present guard selection (OHMS or CABLE).

To retain the present selection, use the EXIT key to back out of the menu

structure and skip the next two steps.

3. To change the guard selection, place the cursor on the alternate selection

and press ENTER.

4. Use the EXIT key to back out of the menu structure.

NOTE Do not use ohms guard with coaxial cabling, or oscillations may occur.

Ohms guard cannot be selected on the 1A or higher range (source or

measure).

Remote command guard selection

Use the :SYSTem:GUARd command (Section 18, “SYSTem subsystem”) to

choose between cable and ohms guard mode via remote. For example, send the

following command to enable ohms guard:

:SYST:GUAR OHMS

Conversely, send this command to enable cable guard:

:SYST:GUAR CABL