How can I offset the voltage drop caused by long cable lengths from my dc power supply to the device under test (DUT)?

Normally, Keysight power supplies are delivered configured to deliver their full specs at the output terminals. In some application, where long lead lengths to the DUT are unavoidable, the regulation of the power supply at the DUT can be significantly improved by using remote sensing. The sense leads effectively connect the inputs to the power supply control loop directly to the DUT. Since there is negligible current in these sense leads, the exact voltage at the DUT is communicated back to the power supply. Now any resistance in the load leads is essentially brought inside the power supply control loop, and is effectively "eliminated"?

The amount of drop in the load leads that the sense leads can correct for is limited. In general, most Keysight dc power supplies can handle up to 2 volts in each load lead. Some power supplies are available which can drop up to half the rated output in each lead. Of course, the total drop in the load leads subtracts from the rated voltage available for the DUT. For more detailed information on remote sensing specifications, click on the Power Product Catalog link.

PROCEDURE:

For the 661xB/C, 663xB, 664xA, 665xA, Loads, 66111A, 66311A, 66312A, 66332A and 6610xA Series:

• Make the sense wire connections (+S to +; -S to the -)
• Ensure that the Remote/Local switch on the back of the unit is set to "Remote"
• Note: front panel binding posts do not have remote sense capability

For the 667xA and 668xA (no Remote/Local switch):

• Remove the jumpers connecting +LS and +S, and connecting -LS and -S
• Make the sense wire connections (+S to +; -S to the -)

For 681xA, 6814B, 6834B and 6843A ac sources (no Remote/Local switch):

• ALWAYS make the sense wire connections (+S to +; -S to the -)

Also, in applications requiring relays, the 59510A/11A Relays automatically switch and sequence both load and sense leads. When used with Keysight system power supplies that have been configured appropriately, the relays can be controlled through the power supply GPIB port. Please refer to the Operating Manuals elsewhere on this website for more complete information on remote sensing.