Additional Load Considerations - All Models - Keysight Technologies RP7900 Serie Guide D'utilisation Et De Maintenance

2 Installing the Instrument
Conversely, if the unit were sinking current, the voltage at the previous remote sense point would rise
by the same amount.
Shorted sense leads are detected by the over-voltage protection function. This function results in the
output being disabled due to an over-voltage fault (OV).
Reversed sense leads are detected by the negative over-voltage protection function. This results in
the output being disabled due to a negative over-voltage fault (OV).
Refer to Additional Load Considerations - RP793xA, RP794xA for information about lead inductance
when using remote sensing with load capacitance and lead inductance.
Over-voltage Protection
Over-voltage protection (OVP) provides a configurable over-voltage protection based on sense lead
voltage. Having the OVP circuit monitor the sense lead voltage rather than the output terminal
voltage allows for more precise voltage monitoring directly at the load.
Note that due to the voltage drop in the load leads, the voltage at the output of the power supply
could be higher than the voltage being regulated at the load. The voltage at the output terminals of
the power supply can never exceed the unit's voltage rating.
Output Noise
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 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.
The noise specifications documented in the RP793xA-RP794xA and RP795xA-RP796xA specification
tables apply at the output terminals when using local sensing. However, voltage transients may be
produced at the load by noise induced in the leads or by load current transients acting on the
inductance and resistance of the load lead. If it is desirable to keep voltage transient levels to a
minimum, place an aluminum or tantalum capacitor, with an approximate value of 10 microfarad per
foot (30.5 cm) of load lead, right across the load.

Additional Load Considerations - all Models

Response Time with External Capacitor
When programming with an external capacitor, voltage response time may be longer than with purely
resistive loads. Use the following formula to estimate the additional up-programming response time:
Response Time = (added output capacitor)X(change in Vout)
(current limit setting)–(load current)
Note that programming into an external output capacitor may cause the RPS to briefly enter constant
current operating mode, which adds additional response time. By setting the proper voltage slew rate
when using an external capacitor, it may be possible to prevent mode crossover into constant current.
Keysight RP7900 Series Operating and Service Guide 83