Larson Davis 831, User Manual

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2-8 Powering the Model 831 Model 831 Manual
Charge Status LED
The charge status is indicated by an LED beneath the power
key as follows:
• LED continuously lit: Charging
• LED not lit: Not charging
• LED flashing at 1/sec: Trickle charging. This is
typically done early in the charging cycle when the
battery is cold, or when the battery has been highly
discharged. The charge rate should increase when these
conditions improve.
External Power Supply
The Model 831 can be powered from a variety of sources
including internal batteries, via the USB port from a
computer, via the USB port from the PSA029 power supply,
via the I/O port from the PSA027 power supply (using
CBL140 or CBL154), from an ex10.8 to +30 Volt
battery, or from an ex10.8 to +30 Volt mains power
source.
USB Port Power
When powering the Model 831 by
external power, Larson Davis
recommends the Model 831-INT
System Interface Unit and the
appropriate Larson-Davis cable for
making the connection to the battery
or batteries. When powered via the USB port by a computer, use of the
computer's USB power is negotiated with the host and
cannot be utilized until permission is granted by the host.
This means that the Model 831 must run on batteries until
allowed by the host to run on USB or external power. If the
batteries cannot provide sufficient power (flat cells) the
Model 831 may not power on. Ensure that the Model 831
has good batteries in order to turn on. If there are no
batteries installed in the instrument, it will use USB power
regardless of negotiation.
The PSA029 is supplied with power
plug adaptors for most areas of the
world. The Model 831 can be powered via the USB port with the
PSA029 external power supply. The PSA029 has an input
operating voltage range of 90 to 274 VAC and a power line
frequency range of 47 to 63 Hz. The output voltage from the
supply is 5 VDC. The PSA029 used a standard USB A to
Mini-B 5-pin cable which connects to the USB connector on
the bottom of the Model 831.
If the Model 831 is operated without
batteries installed and power is
interrupted, data may be lost. With the PSA029 power supply connected and operating at
rated conditions, the Model 831 will operate properly with
or without batteries installed.