Keithley SourceMeter 2460 User Manual page 45

Model 2460 Interactive SourceMeter® Instrument User's Manual Section 5: Measuring low-resistance devices
Hazardous voltages may be present on all output and guard terminals. To prevent electrical
shock that could cause injury or death, never make or break connections to the Model 2460
while the output is on.
To prevent electric shock, test connections must be configured such that the user cannot
come in contact with conductors or any device under test (DUT) that is in contact with the
conductors. It is good practice to disconnect DUTs from the instrument before powering the
instrument. Safe installation requires proper shields, barriers, and grounding to prevent
contact with conductors.
There is no internal connection between protective earth (safety ground) and the LO
terminals of the Model 2460. Therefore, hazardous voltages (more than 30 V ) can appear
rms
on LO terminals. This can occur when the instrument is operating in any mode. To prevent
hazardous voltage from appearing on the LO terminals, connect the LO terminal to
protective earth if your application allows it. You can connect the LO terminal to the chassis
ground terminal on the front panel or the chassis ground screw terminal on the rear panel.
Note that the front-panel terminals are isolated from the rear-panel terminals. Therefore, if
you are using the front-panel terminals, ground to the front-panel LO terminal. If using the
rear-panel terminals, ground to the rear panel LO terminal.
The following figure shows the schematic for the application.
Figure 19: Sourcing current and measuring resistance using a 4-wire configuration
2460-900-01 Rev. A / September 2014 5-3