HP 6034A User Manual page 23

be programmed to operate either as a voltage source (either
the CV (NORMAL) or CC (LIMIT) indicator will be on), or as a
current source (either the
CC
(NORMAL) or CV (LIMIT) in¬
dicator will be on). Note that the 6034A switches between CV
and CC mode in the same way regardless of whether the unit
is programmed to operate as a voltage source or as a current
source. The only difference is whether the 6034A requests ser¬
vice when the unit switches to
CC
or when it switches to CV.
Figure 3-2. Overall Output Range with Three Sample
Operating Loci
3-8 Locus 2 is established with a voltage setting of 35 V
and a current setting of 6.5 A. Its crossover load resistance is
5.4 ohms, and lies on the rated-output-power boundary.
3-9 A rectangular operating locus will be established for all
voltage and current settings within the rated-output-power
boundary. The power supply operates at one point on that
locus, depending on the load resistance. However, if the
voltage and current settings are such that the boundary can be
exceeded, as in locus 3, the supply will go into overrange if the
load resistance fails within a critical band (refer to next
paragraph).
3-10 Overramge. The supply will be driven into overrange
(shaded area of Figure 3-2) if the voltage and current settings
are set above the output power rating and the load resistance
falls within a critical band. For example, assume a voltage set¬
ting of 50 V and a current setting of 8.5 A, as in locus 3 on
Figure 3-2. For all load resistances above 11.9 ohms (which is
the critical value) the supply would operate normally in con¬
stant voltage mode. If the load resistance were to fall much
below 11,9 ohms, however, the supply would be forced into
overrange. If the load resistance continued to decrease to 2.9
ohms, the supply would automatically come out of overrange
and into constant current mode at the 8.5 A, 25 V point. (The
supply will probably go out of regulation while operating in the
overrange region, refer to Paragraph 3-12).
3-11 Anytime the supply operates in overrange, the MODE
indicators turn off and the UNREGULATED indicator lights.
The VOLTS and AMPS meters indicate the voltage and cur¬
rent being supplied to the output, (The product of the two
readings will exceed 200 watts.)
3-12 The supply can operate in the overrange region
(beyond the rated-output-power boundary) for sustained
periods without being damaged, However, the supply is not
guaranteed to meet specifications in overrange. Output ripple
increases substantially and regulation is seriously degraded.
NOTI
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
UNREGULATED 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.
3-14 The 6Q34A performs a self test of its RAM, real-time
clock, and ROM circuits each time power is turned on. The
tests take less than one second to complete, and all indicators
are on while the tests are in progress. If the unit fails self test
the SELF TEST indicator will remain on and some or ail of the
other indicators will remain on. Depending on the location of
the failure, the indicators may flash on and off. Flashing in¬
dicators always indicate a failure, but, because flashing is con
trolled by the microprocessor, a failure may cause the in¬
dicators to remain on without flashing. More extensive inter
rial tests can be accessed in test mode if the unit fails self test
or if there are other indications that the unit may not be
operating properly; refer to Section V,
j CAUTION
Do not enter test mode with load connected.
6034A will indicate test failure and load may be
damaged by 60-volt 1 -ampere output. Refer to
Section V for use of test mode.