The unit can be connected in parallel with others to produce higher currents. Where several units
are connected in parallel, the output voltage will be equal to that of the unit with the highest output
voltage setting until the current drawn exceeds its current limit setting, upon which the output will
fall to that of the next highest setting, and so on. In constant current mode, units can be
connected in parallel to provide a current equal to the sum of the current limit settings.
Protection
The output has intrinsic short-circuit protection and is protected from reverse voltages by a diode;
the continuous reverse current must not exceed 3 Amps, although transients can be much higher.
If the applied reverse voltage can source more current than the set current limit, and the output is
on, then the output will go into current limit (the CC indicator will flash) and its display will show
the reverse voltage across the protection diode; if the output is off, just the CC indicator will flash.
In common with all series regulated single-ended power supplies, the unit is not capable of
sinking current provided from an external source. If a voltage greater than the set output voltage
of the unit is applied from an external source, the internal regulator will turn off and no current will
flow; if the output is turned on the voltage meter will read the applied voltage. No damage will
result providing the applied voltage does not exceed the maximum output voltage of the power
supply by more than 20 Volts.
With the OUTPUT off the load is still connected to the power supply output stage; the output
voltage is simply set to zero. Do not apply external voltages to the power supply terminals in
excess of 20V above the rated output voltage, even with the output off, or damage may result.
Over-temperature Protection
An internal sensor will detect over-temperature due to blocked airflow, fan failure or other circuit
fault. Over-temperature will turn the output off, the OUTPUT indicator will flash, and the display
will show the message
removed, and the instrument has cooled down, the output indicator will go off but the message
OtP triP
continues to show. Pressing the OUTPUT key once will change the display to show
the preset voltage and current (the SETTINGS indicator will be lit) but the output will remain off;
pressing it a second time will turn the output on normally.
If the OUTPUT key is pressed while the instrument is still over-temperature (OUTPUT indicator is
flashing), the message
SETTINGS indicator will be lit) but the output will remain off; each subsequent press of the
OUTPUT key causes the
off until the over-temperature condition ends.
View Settings
Lock Settings
Pressing the LOCK key digitally locks the set voltage and current limit. The settings are stored
with a precision of better than 1 digit. Subsequent adjustments of the VOLTAGE and CURRENT
controls will have no effect.
Because cancelling LOCK will cause the output settings to change if the VOLTAGE and
CURRENT control positions have been moved, warning reminders are given before LOCK is
cancelled. Press and hold the key to cancel LOCK.
If the OUTPUT is off (the safe condition) the display will flash the 'unlocked' settings twice before
the change is implemented; the LOCK lamp goes off.
OtP triP
. When the cause of the over-temperature has been
OtP triP
is replaced by the preset voltage and current (the
OtP triP
message to be displayed briefly but the output will remain
The set voltage and current limit are always shown when
the output is off but can also be viewed when the output is
on by pressing the VIEW key; the SETTINGS indicator is lit
whilst the VIEW key is pressed.
If the output is still on,
display, followed by flashing of the new 'unlocked' settings for 2-3
seconds (slowly at first, then faster) before the change is finally
implemented; the LOCK lamp goes off when the change is made.
OP on
(output on) will flash twice in the
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