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Ecj » VOLTaSC SETTING
Is ' OJRmn SETTING
fti. » LOAD ?^STaNCE
Rq • C«0SS0VE3 f^SlSTANCE
Figure 3-2.
Determining Operating Point
3-10
For load resistances between B and C, the operating
point will be on the maximum output-power boundary between
points 2 and 3, and the OVERANGE LED will be on. The VOLTS
and AMPS displays will indicate the voltage and current being
supplied to the output. (The product of the two readings will
exceed rated output power of the supply.} Note that the ac¬
tual boundary is beyond the specified minimum boundary. The
OVERRANGE LED will light only if the actual boundary is
exceeded.
3-11
The supply can operate in the overrange region for sus¬
tained periods without being damaged. However, the supply
is not guaranteed to meet specifications in overrange. Output
ripple increases substantially and regulation is seriously
degraded.
Under certain conditions of line and load, it is
possible for the supply to provide more than rated
output power and still maintain regulation. If this
occurs, the unit will operate normally and the
OVERRANGE indicator will be off. However, the
slightest change in either line or load may cause
the unit to go out of regulation. Operation of the
unit beyond the rated-output-power boundary is
not recommended under any circumstances.
3-13
The power supply performs a series of self tests each
time power is turned on. All front-pane! LEDs, including
all meter segments, are also turned on. The tests take approx¬
imately one second to complete, and all indicators remain on
while the tests are running. This alerts the operator that self
tests are running, and allows the operator to note if any in¬
dicators are inoperative.
3-14
After the self tests are completed all front-panel in¬
dicators are turned off for one-half second, allowing the operator
to note if any are stuck on. if the operator suspects that any
indicator may be malfunctioning he should turn power off and
back on again while observing that indicator.
3-15
Once the all-indicators-off period is over, the HP-IB
address switch setting is displayed on the meter displays for
one second. For example, if the address switches were set for
address 5, the display would be:
Adr 5
3-16
If the unit fails any of the self tests, an error code is
displayed on the meter displays. The unit will not re¬
spond to any commands, either from the front panel or HP-IB,
and it should be removed for service.
NOTE
Because the power supply is testing itself, it is
not possible to guarantee that the unit will pro¬
vide an unambiguous indication of all possible
failures. For example, a failure in the core of the
microcomputer or in the hardware used to light
the front-panel display may prevent the unit from
indicating that it has failed a test. Refer to the
troubleshooting procedures in Section V if there
is any reason to suspect that the unit may be
malfunctioning.
3-17
The following procedure ensures that the unit is opera¬
tional, and may be used as an incoming inspection check. Refer
to Section V for more extensive performance tests to deter¬
mine that the unit meets specifications. Ensure that the rear-
panel MODE switches are set as shown in Figure 3-4, and that
and Sensing Leads
3-4
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