The following figures illustrate load connections using 2-wire sensing and 4-wire sensing.
Connect the load to the output terminals using separate connecting wires. Keep the wire-pair as short as possible
and twist or bundle it to reduce lead inductance and noise pickup. Keep the load leads under 14.7 meters (50 feet)
per lead because of inductance effects.
Connect the sense leads as close to the load as possible. Do NOT bundle the sense wire-pair together with the load
leads; keep the load wires and sense wires separate. The sense leads carry only a few milliamperes of current and can
be a lighter gauge than the load leads. However, any voltage drop in the sense leads can degrade the voltage
regulation of the instrument. Try to keep the sense lead resistance less than about 0.5 Ω per lead (this requires 20
AWG or heavier for a 50-foot length).
After turning the unit on, activate 4-wire remote voltage sensing by pressing Source Settings > Sense 4w. Refer to
Specifying 2-Wire or 4-Wire Sense.
Open sense leads
The sense leads are part of the output's feedback path. Connect them in such a way so that they do not
inadvertently become open circuited. The power supply includes protection resistors that reduce the effect of open
sense leads during 4-wire-sensing. If the sense leads open during operation, the power supply returns to the local
sensing mode, with the voltage at the output terminals approximately 5% higher than the programmed value.
Over-voltage protection considerations
You must take into account any voltage drop in the load leads when setting the over-voltage trip point. This is
because the OVP circuit senses at the output terminals and not at the sense terminals. Due to the voltage drop in
the load leads, the voltage sensed by the OVP circuit could be higher than the voltage being regulated at the load.
Output noise considerations
Any noise picked up on the sense leads will appear at the output terminals and may adversely affect CV load
regulation. Twist the sense leads or use a ribbon cable to minimize the pickup of external noise. In extremely noisy
environments it may be necessary to shield the sense leads. Ground the shield at the power supply end only; do not
use the shield as one of the sensing conductors.
Keysight E36200 Series User's Guide 39
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