The Model 734A
DC Reference Standard is made up of one
Enclosure and four 732B
DC Standards. The Model 734A-7001
can be purchased
separately as needed for your application. The enclosure
securely holds up to four 732B
DC Standards and/or 732B-7001 External Battery/Chargers
An ac power bus inside the 734A-7001 enclosure powers up to
units with only
one ac line cord. Using the enclosure allows you to rack
is a dc voltage laboratory standard that produces
reference voltages of 10V
and 1.018V. Model 734A
contains four 732B
DC Standards in a
chassis. The 732B
highly stable, rugged and transportable. Its 10V output
excels in stability, and can be
used as your direct link in the traceability chain to
standards. You can use the
1.018V output to transfer the "volt" at the 1.018V
level from one set of saturated
standard cells to another. You can also use the 1.018V
output as a working standard with
older equipment that requires a standard cell voltage input.
The 10V output’s long-term stability, predictable drift
rate, low uncertainty, convenient
level, and immunity to accidental damage make the 732B
the preferred artifact
for maintaining a local standard of voltage. With time
Option 732B-100) the drift rate for the 10V output is given.
This reduces the 10V output
uncertainty from 2 ppm/year to 1 ppm/year.
All outputs of the 732B
can withstand short circuit
indefinitely, without damage to the
instrument or disruption of the state of calibration.
Recovery time for a momentary short
is less than 2 minutes; for an extended short, recovery time
is less than 2 hours.
To maintain calibration as a traceable standard, the 732B
must continue to receive
uninterrupted operating voltage from ac line power or from
the internal battery. If
battery voltage drops too low, the front panel IN CAL
indicator goes out and
recalibration is required.
The internal rechargeable battery (if switched on) protects
the standard from line power
interruption and provides power for hot shipment (shipment
under power). The 732B
outputs are unaffected as you change between battery or ac
line power. Battery operation
with a fully charged battery lasts at least 72 hours. You
can extend battery operation by
connecting an external 12V battery such as Model 732B-7001
to the rear panel
MONITOR/EXT BAT IN connector. Plugging the 732B
into ac line
power for 24 hours
fully recharges the internal battery.
Four front panel indicators show operating status. Model
732B-7001 External Battery
and Charger has all but the IN CAL indicator.
· AC PWR lights when the 732B
is connected to ac line power.
· IN CAL goes out to warn you when the 732B
may have lost
its calibration. This
indicator responds to an excessively large drop in battery
voltage or a large change
in oven temperature. If battery voltage falls below the
level needed to keep the 732B
working normally, the IN CAL indicator extinguishes,
indicating a loss of the state
of calibration. Once power is restored and the output has
been verified, you can reset
the IN CAL indicator.
· LOW BAT blinks to warn you to plug the line cord into ac
power when only a few
hours of battery operation remain.
· CHARGE lights when the battery is being recharged in
mode, and is off when the battery is charged to the 90%
level. At 90% of full charge,
a float charge completes and maintains full charge.