Instructions

Page 17
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 2000 B Single Series
3. Operation and application
3.1 Personal safety
• In order to guarantee safety when using the device, it’s essential that only persons operate
the device who are fully acquainted and trained in the required safety measures to be taken
when working with dangerous electrical voltages
• For models which accept dangerous voltages, a protection against unwanted physical contact
has to be installed on the DC output
3.2 Operating modes
Apowersupplyisinternallycontrolledbydi󰀨erentcontrolorregulationcircuits,whichshallbringvoltageandcurrent
to the adjusted values and hold them constant, if possible. These circuits follow typical laws of control systems
engineering,resultingindi󰀨erentoperatingmodes.Everyoperatingmodehasitsowncharacteristicswhichis
explained below in short form.
• Unloaded operation isn’t considered as a normal operation mode and can thus lead to false
measurements, for example when calibrating the device
• The optimal working point of the device is between 50% and 100% voltage and current
• It’s recommended to not run the device below 10% voltage and current, in order to make
sure technical values like ripple and transient times can be met
3.2.1 Voltage regulation / Constant voltage
Voltage regulation is also called constant voltage operation (CV).
The DC output voltage of a power supply is held constant on the adjusted value, unless the output current reaches
the adjusted current limit. In this case the device will automatically change to constant current operation. Then the
output voltage can’t be held constant anymore and will sink to a value resulting from Ohm’s law.
While the DC output 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 also stored as status which can be read via the digital interface.
3.2.1.1 Transient time after load step
For constant voltage mode (CV), the technical date “Settling time after load step” (see 1.8.3)denesatimethat
is required by the internal voltage regulator to settle the output voltage after a load step. Negative load steps, i.e.
high load to lower load, will cause the output voltage to overshoot for a short time until compensated by the voltage
regulator. The same occurs with a positive load step, i.e. low load to high load. There the output collapses for a
moment. The amplitude of the overshoot resp. collapse depends on the device model, the currently adjusted output
voltageandthecapacityontheDCoutputandcanthusnotbestatedwithaspecicvalue.
Depictions:
Example for neg. load step: the DC output will rise
above the adjusted value for a short time. t = transient
time to settle the output voltage.
Example for pos. load step: the DC output will collapse
below the adjusted value for a short time. t = transient
time to settle the output voltage.