User`s guide

Advanced Source and Measurement Functions 6
Model N6705 User’s Guide 159
Key
Sourcing power
Sinking power
Programmable
V setting
-I limit +I limit
+20 V /
+6 V
-20 V /
-6 V
+1 A /
+3 A
-1 A /
-3 A
+OV
−OV
− Voltage
operation
applies to
N6784A
only
+ Voltage
+ Current
The heavy solid line illustrates the locus of possible operating points
as a function of the output load. As shown by the horizontal portion
of the line, the output voltage remains regulated at its programmed
setting as long as the load current remains within the positive or
negative current limit setting. A CV (constant voltage) status flag
indicates that the output current is within the limit settings.
When the output current reaches either the positive or negative
current limit, the unit no longer operates in constant voltage mode
and the output voltage is no longer held constant. Instead, the power
supply will now regulate the output current at its current limit
setting. Either a CL+ (positive current limit), or CL− (negative
current limit) status flag is set to indicate that a current limit has
been reached.
As shown by the vertical portions of the load line, when the unit is
sinking power, the output voltage may continue to increase in the
positive or negative direction as more current is forced into the unit.
When the output voltage exceeds either the positive or negative over-
voltage setting, the output will shut down, the output relays will
open, and either the OV or OV- and the PROT status bits will be set.
Either the user-defined over-voltage setting or the local over-voltage
function can trip the over-voltage protection.
Current Priority Mode
In current priority mode, the output current should be programmed
to the desired positive or negative value. A positive voltage limit
value should also be set. The voltage limit should always be set higher
than the actual output voltage requirement of the external load. With