Tenma 72-6851 & 72-6853 Instruction manual
Manual Operation
Front Panel
The POWER switch is used to apply line voltage to the instrument. When switched to on (
l
) the
instrument will be powered and the start-up procedure will be executed; this will take
approximately 5 second to complete. If all is well the settings from the last power-down will be
installed and the instrument will be ready for use.
The output terminals are located on the right of the front panel. The red terminal is positive and
the black terminal is negative. Connection to the output terminals can be made with any of the
following: 4mm plugs, spade terminals or wire ends. To minimise voltage drop, the connecting
leads to the load should be of an adequate wire gauge and be kept short. The output terminals
are duplicated on the rear panel, together with the sense terminals.
The keyboard is located to the left of the output terminals. This consists of 27 keys and a LED
indicating the instrument output status. The use of the keyboard to control all instrument functions
is discussed in the following sections.
To the left of the keyboard is the status display which consists of a 4-digit, 7-segment display and
10 LEDs. Normally the status display will show the output power (in Watts) when the output is on
or will be blank when the output is off; however, other information will appear when selections are
made from the keyboard. The relevant annunciator LED will indicate what the contents of the
display represent at any time.
Above the keyboard are the main displays and LED indicators which show the conditions of the
output. The displays show the set voltage and set current when the output is off and the voltage
at the output terminals and output current when the output is on.
To the right of the LED indicators is a continuously rotating control which may be used to make
fine adjustments to voltage or current as described later.
General Principles of Manual Operation
The following sections explain in detail the use of the keyboard to control all instrument functions.
If an error is encountered during keyboard operation the status display will show
Ennn
where nnn
is a decimal number. A full list of possible errors is given in the STATUS REPORTING section.
Set Voltage
The set voltage is normally shown in the top left hand display marked V. The exception to this is
when the output is on and in constant current (CI) mode. In this case the actual output voltage will
be less than the set value and will be shown instead.
To set the voltage press the VOLTS key. The status display will show the set voltage value and
the VOLTS LED will light. A new value may now be entered from the numeric keypad. The value
will be in Volts and the POINT key may be used to enter decimal digits. Once the required value
is entered press the CONFIRM key and the set voltage will be updated immediately. To exit
without making any changes press the ESCAPE key. If a mistake is made during entry press the
VOLTS key and start again. The maximum and minimum values accepted will depend on the
particular model, see the specification section for details.
Set Current
When the output is off the set current is shown in the top right hand display marked A. When the
output is on and in constant voltage (CV) mode the output current is shown. When in constant
current (CI) mode the output current is equal to the set current and this is shown.
To set the current press the AMPS key. The status display will show the set current value and the
AMPS LED will light. A new value may now be entered from the numeric keypad. The value will
be in Amps and the POINT key may be used to enter decimal digits. Once the required value is
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