Tracking; Safety Features; Current Limit; Electronic Fuse - Hameg HM8143G Manual

S a f e t y f e a t u r e s
16 V
13 V
10 V
6 V
3 V
0 V
If a modulation voltage of 2 V
minal value of the output voltage of the HM8143
must not exceed 24.00 V.
STOP
If the ground of the modulations source is con-
! nected with the saftey ground terminal , the mo-
dulation source has to be operated via an isolation
transformer , as there will be no electrical isola-
tion of the power supply.

Tracking

With the aid of the tracking function, it is possible to simulta-
neously vary 2 setting parameters of the two 30 V-channels.
In other words, either both output voltage settings or both cur-
rent limits can be varied at the same time by using the tracking
function. This function is activated by pressing the TRACKING
button . The TRACKING LED is lit. To exit the tracking mode,
press the TRACKING button
This has the effect of clearing all previously activated functions,
and from then on whenever a value is called and changed both
channels of the instrument are identically affected (the 5 V out-
put remains unchanged). It does not matter which values had
been set prior to changing one of the parameters; in the tracking
mode, the HM8143 always retains the respective differences
between the voltages values and the current limits, except if
the minimum or maximum values of current limit (0.005 A or
2 A) or of the output voltage (0 V or 30 V) is reached. In this case,
the difference of voltage or current will be reduced as long as
it will be zero. That means until the values of the output volta-
ge or current limit of both channels have set to the minimum
or maximum values.
26
Subject to change without notice
channel II
channel I
is applied, the no-
pp
again .

Safety features

The HM8143 is equipped with a variety of safety features to
prevent damage being caused to the instrument by short cir-
cuits or overheating.

Current limit

If one of the output voltages is short circuited, the current li-
miter automatically keeps the current from rising beyond the
programmed maximum output current. The response time is
approx. 200 μs that means during this time the maximum cur-
rent value set can be exceeded.

Electronic fuse

In order to provide a still better protection than current limi-
ting offers the HM8143 features an electronic fuse. As soon as
I is reached all outputs will be immediately simultaneously
max
disabled.
They may be turned on again by depressing OUPUT
tronic fuse is activated by operating the FUSE button
FUSE LED is on. By pushing the FUSE button
tronic fuse is deactivated. The fuse LED is dark.

Cooling

The heat generated in the HM8143 is removed by a temperature
controlled fan. This is located together with the heat sink in a
"cooling channel" that runs straight through the instrument.
Air is drawn in on the righthand side of the unit and blown out
again on the lefthand side. This also prevents excessive dust
accumulation. Always make sure that there is suffi cient open
space for cooling on both sides of the HM8143.
In no case may the cooling holes on the sides of the
unit be covered.
If the temperature inside the HM8143 should nevertheless
STOP
rise to above 80 °C, an automatic temperature-controlled safe-
ty circuit is activated. The outputs are put off. After the unit has
cooled down suffi ciently, operation can be resumed by pressing
the OUTPUT button .

Error messages

In case of a mal function the HM8143 will display an error mes-
sage on the left display (channel I):
Display Meaning
E1 Error channel I
E2 Error channel III
E3 Error channel II
Please turn off the instrument if one of these errors occurs. If
the error is still displayed after resetting the instrument, it has
to be sent in. Please contact the HAMEG service department
(Tel: +049 (0) 6182 800 500, E-Mail: service@hameg.de).
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