Hameg Instruments HM 8040-2 Manuel page 13

Operating instructions
The Triple Power Supply HM8040-2 has
electrically isolated supply voltages. This
permits easy series connection of all output
voltages and parallel connection of both
adjustable 0-20V Supply voltages.
Safety Advice:
The HM8040-2 may exceed the safety
low-voltage of 42V if all output voltages
are connected in series. This might lead
to danger when touching voltage-car-
rying areas. lt is therefore strongly re-
commended that the HM8040-2 is opera-
ted only by qualified personnel acquain-
ted with the dangers involved.
The maximum current to be drawn from
the HM8040-2 in series connection is limited
to 0.5A. Parallel connection of the output
voltages (0-20V) increases the maximum
current to 1 A. The output voltage remains
at 20V. Individual instrument settings, i.e.
internal resistance, noise, may change if
parallel or series connection are utilized.
HM8040-2 Output Power
The HM8040-2 utilizes the supply
voltages resident in the mainframe unit
HM8001-2 and is limited in its maximum
output power. The HM8040-2 may only be
used in the HM8001 or HM8001-2 if the
output power of 25W (HM8040 - 18.5W) is
not exceeded.
Special consideration should be given to
the maximum power drawn when 2 triple
power supplies are operated in one main-
frame unit. The operation of two HM8040-2
modules in one mainframe unit is permitted
only if the total power for both units does
not exceed 36W, and if the single output
power as well as the output currents of the
triple power supplies do not surpass limits
of the respective mainframe unit. lt is
important to assure proper cooling while
operating the HM8040-2.
Operation of HM8040-2
with the HM8001 Mainframe
Please note that the maximum output
currents of the HM8040-2 can only be
achieved in combination with the HM8001-
2 mainframe unit. This combination
guarantees safe and error-free operation
when elevated output currents are drawn.
Output currents of 0.4A at 20V and 0.5A at
5V may not be surpassed when using a
HM8001 mainframe unit. Failure to comply
with this guideline may lead to damaged
rectifiers in the HM 8001 mainframe.
14
Operation
The LEDs of the HM8040-2 constantly
displays the output voltages or output
currents of the two adjustable 20V sources.
The voltage display also operates when
outputs are switched off and allows for a
pre-adjustment of the desired output voltage
without any load connected. lt is advised to
switch on the output voltages only after
correct setting of voltage levels has been
made.
Current Limitation
The current limitation for the 20V sources
is adjustable on either side within the range
of 10mA to 500mA. A small screwdriver is
necessary to perform the adjustment of the
trimpot, for current limitation, which is
located behind the front panel below the
displays. The current limitation for the 5V
source is fixed at 1A.
Functional Test
The HM8040-2 should regularly be tested
to assure proper functioning. The following
test checks out the module's performance
and supplies suggestions for adjusting
specific values.
The adjustment will only be meaningful
if the below indicated or equivalent
instruments are used. Prior to the functional
test or adjustment, the instrument has to
reach its operating temperature: power up
module in mainframe HM8001-2 for at least
one hour. All specifications apply to an
ambient temperature of 23°C ± 1°C.
Prior to opening the instrument, the
notices in chapters "Safety", "Warranty",
and "Service" should be reviewed carefully.
For test and adjustments it is suggested to
use adapter unit HM8080. The use of a
shielded cable for connection between
measuring instrument and the instrument
to be adjusted is highly recommended, in
order to avoid undesirable outside influences
on measuring signals.
Necessary Measuring Equipment
1 Digital Voltmeter, i.e. HM8011-3
1 Oscilloscope, i.e. HM303
1 Resistor 2kOhm 1%
Test Procedure
Individual steps of the following test
sequence may be combined with other test
steps, especially display accuracy.
Änderungen vorbehalten / Subject to change without notice