Operating the Power Supply Locally
3
Series N5700 User’s Guide
39
CV/CC Mode Crossover
If the power supply is in constant voltage mode and the load current
increases above the current limit setting, the power supply switches to
constant current mode. If the load decreases below the current limit
setting, the power supply switches to constant voltage mode.
CV/CC Signal
CAUTION
Do not connect the CV/CC signal to a voltage source higher than 30VDC.
Always connect the CV/CC signal to the voltage source with a series resistor to
limit the sink current to less than 10mA.
The CV/CC signal available on the J1 connector indicates the operating
mode of the power supply. The CV/CC signal is an open collector output
with a 30V parallel zener at J1 pin 13, referenced to common at J1 pin 12.
J1 pin 12 is connected internally to the –S terminal. When the power
supply operates in constant voltage mode, CV/CC output is open. When
the power supply operates in constant current mode, CV/CC signal
output is low (0 - 0.6V), with maximum 10mA sink current.
Protection Functions
Over-Voltage Protection
The over-voltage protection protects against over-voltage conditions on
the output. If the output voltage attempts to exceed the programmed limit
in response to an analog programming signal or in the event of a power
supply failure, the over-voltage protection circuit will protect the load by
disabling the output. The voltage is monitored at the sense terminals,
thus providing the protection level directly at the load. Upon detection of
an over-voltage condition, the output is disabled, the display shows OVP,
the PROT indicator blinks, and OV is set in the Questionable Condition
status register.
Adjustment of the over-voltage setting can be made when the output is
enabled (On) or disabled (Off). To set the OVP level, press the OVP/UVL
button so that the display indicates OUP. The display will show the OVP
setting. Rotate the voltage knob to adjust the OVP level. The display will
show OVP and the setting value for another five seconds and then return
to its previous state.
The OVP settings are limited at the minimum level to approximately 5%
above the output voltage setting. Attempting to adjust the OVP below this
limit will result in no response to the adjustment attempt. Refer to
Appendix A for the maximum OVP settings.
Use one of the following methods to reset the OVP circuit after it
activates. If the condition that caused the over-voltage shutdown is still
present, the OVP circuit will turn the output off again.
•
Press the OUT ON button to turn the output on.
