54
Advanced Operating Functions
54
Advanced Operating Functions
6.4 External Trigger
You can create an external trigger signal (TTL) to the volt-
age interface on the back panel of the instrument to start
an arbitrary function, for instance, to activate and deacti-
vate sequencing or to activate data logging.
6.5 EasyRamp
The power supply includes a EasyRamp function allow-
ing the user to simulate a startup curve. After switching
on the channels (MASTER ON), the increase in output
voltage and output current will be approximately linear
to the set voltage and current value. Use the soft menu
key TIME to select the time value during which the volt-
age and current values are intended to increase. You can
modify the time value via knob in 10 ms increments or via
numeric keypad. You may enter any time value between
10 ms and 10 s. The soft menu key ACTIVATE enables
you to activate (ON) or deactivate (OFF) each channel
separately. The start time (TIME) is also selected individu-
ally for each channel. Once you have activated one or
multiple channels and you use the MASTER ON/OFF key
after activating the channels (CH1 ON/OFF, CH2 ON/OFF,
CH3 ON/OFF), the increase in voltage and current values
will be shown in the display.
6.6 Parallel and Serial Mode
To increase output voltage and currents, it is possible
to operate the channels in serial or parallel mode. These
operating modes require that power supplies are suitable
for the parallel and/or serial mode. In general, the output
voltages to be combined are independent. The outputs for
one or multiple power supplies can be interconnected for
this purpose.
EasyRamp can not be used with Analog In and arbitrary function
simultaneously.
Fig. 6.7: EasyRamp example
It is assumed that only qualified and trained personnel service the
power supplies and the connected consumers.
A serial connection may cause dangerous voltages.
CH1
CH2
CH3
64 V
1 A
32 V
1 A
32 V
1 A
Fig. 6.8: Example for serial mode
6.6.1 Serial Mode
This type of interconnection adds the individual output
voltages. The same current flows through all outputs. The
current limits for the outputs wired in series should be set
to the identical value. If one of the outputs exceeds the
current limit, the total voltage will naturally collapse. It is
advisable to set both voltages to a similar value to distri-
bute the loads evenly (not absolutely necessary). If a (low
resistance) load is connected, it is essential to activate
more than one channel. This could damage the instrument
(especially protective diodes). Therefore, it is necessary to
always have both channels or no channel at all switched
on.
If the instrument switches to constant current operating mode
(CC) during a serial connection, the voltage display becomes inac-
curate.
6.6.2 Parallel Mode
If it is necessary to increase the total current, the power
supply outputs must be wired in parallel. The output
voltages for the individual outputs should be set to the
same voltage value as precisely as possible. For slight
voltage differences, it is common in this operating mode
to first charge a voltage output up to the current limit; the
other voltage output provides the remaining current. The
maximum total current is the sum of the individual cur-
rents of all sources connected in parallel. For power
supplies that are connected in parallel, It is possible that
compensating currents flow within the power supplies.
The use of power supplies by other manufacturers, which
are potentially not overload proof, can cause destruction of
these units as currents may be distributed unevenly.
Generally, a higher current will first be supplied from the
channel with the higher output voltage. Once this channel
reaches its power limit, the remaining current will be made
available by the channel that is connected in parallel. In
this scenario, it is unpredictable which channel will supply
the higher current because it is also possible for channels
with identical voltage values to display a low voltage dif-
ference. If you distribute the load to multiple channels, it is
By increasing the voltage slightly, the load distribution can be
manipulated. If the voltage for a channel is to be increased by
50mV, for instance (by a set of identical cables), the current will
initially be provided by this channel.
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