Keysight RP7970 Serie Manuel D'utilisation page 165

Note that when the output voltage reaches the voltage limit, the unit no longer operates in constant
current mode and the output current is no longer held constant. Instead, the power supply will now
regulate the output voltage at its voltage limit setting. A LIM+ (positive voltage limit) status is set to
indicate that the voltage limit has been reached. This condition is annunciated by VL+ on the front
panel.
As shown by the horizontal portion of the load line, when the unit is sinking power, the output current
may continue to increase in the negative direction as more current is forced into the unit. This can
happen when the load is a power source such as a battery, and its output voltage is higher than the
voltage limit setting of the power supply. Once the current exceeds the built-in negative over-current
limit, the output will shut down, the output relays will open, and the OCF status bits will be set. In such
a case, it is important to set the voltage limit properly in order prevent this protection shutdown.
For additional information on priority mode operation during output turn-on/turn-
off, refer to
Keysight RP7970 & RP7980 Series Operating and Service Guide
Turn-On Turn-Off Behavior.
4 Using the Regenerative Power System
165