11
Initial Operation
This section of the manual is a general introduction to the controls and operation of the instrument
and is intended to be read before using the power supply for the first time. In this manual front
panel keys, connections and indicators are shown in capitals, e.g. ESCAPE, JOG SET, OUTPUT,
ON. Messages shown on the display are printed in a different type-font, e.g.
Enter V
,
Limits
,
CV
,
Store
.
Switching On, Output On/Off
The power switch is located at the bottom left of the front panel.
At power-up the default behaviour is for the instrument's settings to be restored to those
automatically saved when it was switched off, but with the outputs in independent mode and
always off (
OFF
is shown at the top right-hand side of each output’s display). However, the user
can change this default setting such that the power-down status of the individual outputs and of the
tracking mode are restored at power-up, see the Extra Functions section.
Each DC Output is switched on and off electronically with alternate presses of its
key; the ON
lamp illuminates when the Output is on. At the same time the message above the VOLTS and
AMPS display changes from
OFF
to
CV
(constant voltage) or
CI
(constant current) to indicate
the present operating mode; should the load cause the instrument to operate outside its
guaranteed power range the display will instead show
UNREG
(unregulated). Alternatively, the
BOTH ON or BOTH OFF keys can be used to switch both outputs on or off together; the outputs
switch synchronously within <10
µ
s of each other. Note that, if one output is already on and the
other off, BOTH ON will turn the off output on and BOTH OFF will turn the on output off.
Select Output
The output to be adjusted is selected by pressing CONTROL 1 or CONTROL 2; the corresponding
LED lamp will light to show which output is currently under the control of the numeric keypad or
rotary control. Note that the individual
ON keys, as well as the
BOTH ON and
BOTH
OFF keys, will always operate regardless of which output is currently selected by the CONTROL
keys. Control of Output 1 is the default setting at power-up.
Keypad
Only the principles of operation are outlined here; the setting of individual parameters is given in
detail in later sections. The paramount consideration in designing the user interface has been to
make changing settings as 'safe' as possible (i.e. with minimal risk of accidentally applying
excessive voltages to a load) whilst achieving ease of use. This has been achieved by requiring
the user to confirm (OK) new numeric settings, with the option to ESCAPE at any point or even to
simply pause until the operation times-out and the instrument returns to its original settings. In
addition, display messages and LED indicators prompt, guide or warn the user such that entry or
control errors are minimised. Where some of these features (e.g. beeps) are considered
unnecessary by regular users, the option exists to disable them, see the Extra Functions section.
Press CONTROL 1 or 2 to select the output to be adjusted. Under normal conditions the numeric
keypad is disabled; any numeric key presses will simply be ignored. To set a voltage with the
keypad first press the V NUMERIC SET key; the VOLTS display changes to show the present set
value in a smaller font, with the message
Enter V or ESC
below it, and the OK lamp starts
flashing. The new value is then entered from the keyboard; as it is entered it is displayed directly
below the present setting, replacing the prompt message. At any time during entry the new setting
can be confirmed with the OK key, e.g. it is sufficient to key in 1, OK to change the setting to
1Volt. When OK is pressed the display reverts to show just the new setting in the full-size font and
the OK lamp stops flashing; if OK is not pressed within 10s of the last numeric key the entry is
cancelled and the display returns to its original setting. If ESCAPE is pressed anytime in the entry
procedure, entry is cancelled and the display returns to its original setting. The current limit is set in
exactly the same way after first pressing I NUMERIC SET.
The OK key is used to confirm most keypad entries. At all other times it becomes the VIEW V/I
LIMITS key and pressing it will cause the display to show preset output voltage and current limit for
3 seconds; during this period the
Limits
message shows in the display.
