6RL SERIES OPERATION MANUAL
SECTION 3: PRODUCT OVERVIEW
Entire Contents Copyright
2018 by Adaptive Power Systems, Inc. (APS) • All Rights Reserved • No reproduction without written authorization from APS.
6RL Series Regenerative DC Load Operation Manual
Page 18 of 204
3.4
Operating Modes
An electronic load is internally controlled by different control or regulation circuits, which
control voltage, current and power to the adjusted values and hold them constant, if
possible. These circuits follow typical laws of control systems engineering, resulting in
different operating modes. Every operating mode has its own characteristics, which is
explained below in short form. The 6RL Series programmable DC power supplies support the
following operating modes:
Constant Current (CC) mode
Constant Power (CP) mode
Internal Resistance (IR) mode
Constant Voltage (CV) mode
3.4.1
Constant Voltage (CV) Mode
Constant voltage operation (CV) or voltage regulation is a subordinate operating mode of
electronic loads. In normal operation, a voltage source is connected to electronic load,
which represents a certain input voltage for the load. If the set value for the voltage in
constant voltage operation is higher than the actual voltage of the source, the value cannot
be obtained. The load will then take no current from the source. If the voltage set value is
lower than the input voltage then the load will attempt to drain enough current from the
source to achieve the desired voltage level. If the resulting current exceeds the maximum
possible or adjusted current value or the total power according to P = UIN * IIN is reached,
the load will automatically switch to constant current or constant power operation,
whatever comes first. In that case, the set input voltage can no longer be achieved.
While the DC Input is switched on and constant voltage mode is active, the condition “CV
mode active” will be indicated on the display by the abbreviation CV and this message will
be passed as a signal to the analog interface. It is also stored as status condition, which can
be read as a status message via the digital interface.
3.4.1.1
Voltage Control Loop Speed
The internal voltage control loop can be switched between “Slow” and “Fast” (see section
6.4.3.2, “General Settings Menu” on page 67). Factory default value is “Slow”. Which setting
to select depends on the actual situation in which the device is going to be operated, but
primarily it depends of the type of voltage source connected. An active, regulated source
such as a switching mode power supply has its own voltage control loop, which works
concurrently with the load’s circuit. Both might work against each other resulting in
oscillation. If this occurs, it is recommended to set the controller speed to “Slow”.
In other situations, e.g. operating the function generator and applying various functions to
the load’s input voltage and setting of small increments, it might be necessary to set the
voltage controller to “Fast” in order to achieve the expected results.
Summary of Contents for 6RL Series
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