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zero and OVERVOLTAGE indicator comes on), turn
Off the supply and then disconnect any load from
the power supply.
Turn the supply back on and
determine if the crowbar again trips.
If it does,
there is a problem in the power supply.
Refer to
Section V for troubleshooting procedures that can
be used to isolate the cause of the overvoltage
condition.
If the supply does not crowbar when
the load is removed, check the load circuit or the
trip point setting.
3-16 Crowbar Terminals.
Terminals A13 and A14
at the rear of the supply allow the crowbar trigger
to be either monitored by an external circuit or to
be used to trip crowbar circuits in other precision
power supplies (by interconnecting the A13 and A14
terminals).
If precision power supply crowbars
are to be interconnected, be sure that ail A13 term¬
inals (the positive terminal) are connected and all
A14 terminals are connected (see figures 3-9
through 3-11),
The crowbar trigger pulse specifi¬
cations are given below and assume that no sup¬
plies are interconnected:
Input Trigger Pulse:
Voltage: 3V minimum, 10V maximum
Width
(between 90% point at leading edge and
90%.point at falling edge):
lOpsec minimum.
Output Pulse:
Voltage:
5±1V
Rise and Fall Time (between 10% and 90% points):
200nsec.
Width:
15±3 usee.
Load Impedance:
lOr/min.)
3-17 CONNECTING LOAD
3-18 Each load should be connected to the power
supply output terminals (front or rear) using separ¬
ate pairs of connecting wires.
This will minimize
mutual coupling effects between loads and will re¬
tain full advantage of the low output impedance of
the power supply.
Each pair of connecting wires
should be as short as possible and twisted or
shielded to reduce noise pickup.
(If a shielded
pair is used, connect the shield to ground at the
power supply and leave the other end unconnected.)
3-19 If load considerations require that the output
power distribution terminals be remotely located
from the power supply, then the power supply out¬
put terminals should be connected to the remote
distribution terminals via a pair of twisted or
shielded wires and each load should be separately
connected to the remote distribution terminals.
For
this case, remote sensing should be used.
(Refer
to paragraph 3-3 6)
3-20 Positive or negative voltages can be obtained
from the supply by grounding either one of the out¬
put terminals or one end of the load.
Always use
two leads to connect the load to the supply, re¬
gardless of where the setup is grounded.
This will
eliminate any possibility of output current return
paths through the power source ground.
The supply
can also be operated up to 300Vdc above ground if
neither output terminal is grounded.
3-21 OPERATION BEYOND NORMAL RATED OUTPUT
3-22 The shaded area on the front panel meter
face(s) indicates the amount of output voltage or
current that may be available in excess of the nor¬
mal rated outputs (each supply is rated for two
voltage/current ranges).. Although the supply can
be operated in this shaded region without being
damaged, it cannot be guaranteed to meet all of
its performance specifications.
Generally, when
operating the supply in this manner, the output is
unstable when a load is connected.
However, if
the line voltage is maintained above its nominal
value, the supply will probably operate within the
specifications above the rated output.
In addition,
the supply may be operated slightly above (approx¬
imately 130% at nominal line voltage) the voltage/
current range specifications (i.e. at about 1.3A up
to 40V for the 6104A/6114A or at about 0.52A up to
100V for the 6105A/6115A; or at 2A up to 26V for the
6104A/6114A or . 8A up to 65V for the 6105A/6115A),
In these operating regions, however, the supply is
in gross current limit and certain power supply
specifications (such as ripple, etc.) are degraded.
3-23
REMOTE PROGRAMMING, CONSTANT VOLTAGE
3-24 The constant voltage output of the power
supply can be programmed (controlled) from a re¬
mote location if required.
Either a resistance or
voltage source can be used as the programming
device.
The wires connecting the programming
terminals of the supply to the remote programming
device should be twisted or shielded to reduce
noise pickup.
The front panel VOLTAGE control is
automatically disabled in the following procedures.
3-2 5 Resistance Programming (Figure 3-3).
In this
mode, the output voltage will vary at a rate deter-
mlned by the programming coefficient — 2000 ohms
[
Al A2 A3 A4 A5 A6 A7
i
F
m
1
E in
1
1
A8 +
□
F
m
R !□
El
\-I
m
Figure 3-3.
Remote Resistance Programming
(Constant Voltage)
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