User manual

Page 30
EA Elektro-Automatik GmbH
Helmholtzstr. 31-37 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
www.elektroautomatik.de
[e-mail]
PS 3000 C Series
3.2.2 Current regulation / constant current / current limitation
Current regulation is also known as current limiting or constant current mode (CC).
The DC output current is held constant by the power supply, once the output current to the load reaches the adjusted
limit.ThenthepowersupplyautomaticallyswitchesThecurrentowingfromthepowersupplyisdeterminedbythe
output voltage and the load’s true resistance. As long as the output current is lower than the adjusted current limit,
the device will be either in constant voltage or constant power mode. If, however, the power consumption reaches
the set maximum power value, the device will switch automatically to power limiting and sets the output current
according to I
MAX
= P
SET
/ U
IN
, even if the maximum current value is higher. The current set value, as determined
by the user, is always an upper limit only.
While the DC output is switched on and constant current mode is active, then the condition “CC mode active” will be
indicated on the display by the abbreviation CC and this message will be passed as a signal to the optional analog
interface, as well stored as status which can also be read as a status message via the optional digital interfaces.
3.2.3 Power regulation / constant power / power limitation
Power regulation, also known as power limiting or constant power (CP), keeps the
DCoutputpowerofapowersupplyconstantifthecurrentowingtotheloadin
relation to the output voltage and the resistance of load reaches the adjusted value
according to P = U * I resp. P = U² / R. The power limiting then regulates the output
current according to I = sqr(P / R), where R is the load’s resistance.
Power limiting operates according to the auto-range principle such that at lower
outputvoltageshighercurrentowsandviceversainordertomaintainconstant
power within the range P
N
(see diagram to the right).
While the DC output is switched on and constant power mode is active, then the
condition “CP mode active” will be shown on the display by the abbreviation CP, as
well stored as status which can also be read as a status message via the optional
digital interfaces.