12
Range and Test Current
Indicates the range selected and the test current level used.
Local/Remote Indicator
This section of the display indicates the remote/local state of the instrument. If RMT is displayed, the
instrument is in remote state and can only receive commands through its remote interface port. If the
section is blank, the 4314Ki is in local state and will receive commands from the front panel keys.
Range Selection Keys
The eight range keys allow the user to select the required measurement range of the instrument. Each
key is labeled with the respective range value.
Source and Sense Post
Connections to the 4314Ki are made via the front panel source/sense terminals, which consist of two red
and two black standard binding posts. The posts can accept standard banana plugs, wires up to 12 AWG,
or spade lugs. The four terminals provide full 4-Wire Kelvin measurement capability. The right posts are
the positive and negative current source terminals and provide the test current, while the left posts are
the positive and negative voltage sense terminals used to monitor the voltage drop across the load.
The 4-Wire configuration eliminates errors normally caused by test lead and contact resistances. In many
applications, the contact resistance can exceed the value of the load by several orders of magnitude. The
4314Ki bypasses this potential error source by providing two terminals of constant current and an
additional two terminals for high impedance voltage sensing. The result is a fast, accurate resistance
measurement of the load, independent of the resistance of the current carrying leads. Later in this chapter
we will illustrate how the 4-wire principle is used to eliminate lead, wire, and contact resistances as
potential error sources.
