Xantrex XTR 100-17, Operating Manual

Page: 59 / 274

Standard Operation
975-0200-01-01 3-11
3
Output disabled The mode of operation is not determined until the output is enabled. The
CV and CC mode LEDs will not indicate the mode while the output is
disabled.
Constant Voltage Mode Operation
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.
Constant Current Mode Operation
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
SET
. The unit is now operating in CC mode. The
voltage will still vary to meet any changes in required output voltage
resulting from a change in the attached load.
Automatic Mode Crossover
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 3-3 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
SET
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
SET
value.