Xantrex XTR 850 WATT SERIES Operating Manual page 56

Local Operation
Constant Voltage Mode Operation
Constant Current Mode Operation
Automatic Mode Crossover
3-12
If the output is enabled and the configured current set point is much
higher than the requirements for the attached load, then the voltage will
rise until it reaches the voltage set point. When the output voltage reaches
the voltage set point, it stops rising. The unit will continue to operate in
CV mode. The load current will still vary to meet any changes in required
load current draw resulting from a change in the attached load.
If the output is enabled, the voltage and current start to rise. At this time
the unit is operating in CV mode (default operational mode). As the load
current drawn reaches the value of the output current setting, the unit will
switch to CC mode and not allow any additional current to be drawn
above the value of I
voltage will still vary to meet any changes in required output voltage
resulting from a change in the attached load.
Mode crossover occurs when the unit makes the switch between operating
modes. Crossover can occur from CV to CC or vice versa, depending on
how the attached load resistance changes. Figure 3-4 shows the
relationships between the variables.
For example, if the unit was initially operating in CV mode with the
output voltage at the voltage set point and the load current below the I
and the attached load resistance began to decrease, the current would rise
to meet this change in the load. The load current will increase in
proportion to the decrease in the load resistance until the load current
drawn reaches the current set point. At this point further decreases in load
resistance (increased load current requirements) will cause the unit to
cross over into CC mode where the output voltage will vary with
changing load resistance and the load current will remain at the I
value.
The reverse operating mode change can also occur if the load resistance is
increased to the point that the required load current drops below the I
value. At that point the power supply would crossover to CV mode and
the load current would be free to vary as the load resistance changed.
. The unit is now operating in CC mode. The
SET
SET
SET
SET
M370046-01