Wire Remote Sensing Connections - Keithley 2600B Reference Manual

Series 2600B System SourceMeter® Instrument Reference Manual

4-wire remote sensing connections

When sourcing and/or measuring voltage in a low-impedance test circuit, there can be errors
associated with lead resistance. Voltage source and measure accuracy are optimized by using 4-wire
remote sense connections. When sourcing voltage, 4-wire remote sensing ensures that the
programmed voltage is delivered to the DUT. When measuring voltage, only the voltage drop across
the DUT is measured.
By default, the Series 2600B instruments are configured to use 2-wire or local voltage sensing. If you
choose to enable 4-wire or remote voltage sensing, then it is critical that you establish and maintain
the proper Kelvin connections between the corresponding force and sense leads to insure the proper
operation of the instrument and to obtain accurate voltage measurements. Sense HI must be
connected to Force HI, and Sense LO must be connected to Force LO.
When sourcing voltage with remote sense, the instrument relies on the voltage detected with the
sense lines to provide the proper closed-loop control of its output voltage. If a sense line becomes
disconnected from its corresponding force line, then an erroneous voltage will be sensed and the
output voltage may be adjusted to a level that is radically different than the programmed voltage level
(possibly to hazardous levels).
When sourcing current with remote sense, the instrument relies on the voltage detected with the
sense lines to properly limit the voltage across the device under test. If a sense line becomes
disconnected from its corresponding force line, then erroneous voltage will be sensed and the voltage
across the device may exceed the programmed source limit voltage, possibly causing damage to the
device or test fixture.
In both cases, the voltage will not be measured correctly if a sense lead becomes disconnected from
its corresponding force lead.
You can use 4-wire remote sensing at any time, however, it is strongly recommended for the following
source-measure conditions:
•
Sourcing or measuring voltage in low impedance (<1 kΩ) test circuits.
•
Enforcing voltage compliance limit directly at the DUT.
For the Models 2601B, 2602B, 2611B, 2612B, 2635B, and 2636B (not 2604B/2614B/2634B), you
can use the built-in contact check function to verify that the force and sense leads are properly
connected together before enabling remote sensing, or before turning on the output. Refer to
Contact check measurements
When using 4-wire local sensing connections, make sure to properly configure the Series 2600B
Sense mode selection
2600BS-901-01 Rev. C / August 2016
(on page 2-45).
(on page 2-75).
Section 2: General operation
2-55