User Manual

10
Manual Operation
Power
The instrument has three possible sources of power: the internal rechargeable battery, DC input
from the AC/DC adaptor/charger supplied (referred to in this manual as the AC adaptor), or USB
power from a USB host port on a desk-top or portable PC. The AC adaptor, if present, will be
used in preference to USB power or the battery; without the AC adaptor, USB will take preference
over the battery; only if neither the AC adaptor nor USB power is present will the battery be used.
The instrument software remembers the power-up cause and conditions and acts intelligently at
loss of AC adaptor or USB power to ensure that the battery is not discharged unintentionally.
Power-up and power-down operation for all possible combinations of conditions are detailed in
the sections that follow.
Safety Warning: The TF960 is a safety class III instrument by IEC classification. When the
instrument is operated from its internal battery, AC adaptor or USB port of a portable
(ungrounded) PC, all accessible parts will be at the same voltage potential as the outer of the
N-type and BNC input sockets; to maintain user safety it is therefore essential that no signal input
is connected to a voltage above 30V dc or 30Vrms, the limit of Safe Extra Low Voltage. Note that
although the inputs will withstand accidental short-term connection to an AC line voltage up to
250Vrms, 50/60Hz, users will be at risk if the instrument ‘ground’ is connected to such hazardous
voltages.
Battery Operation
The instrument is fitted with rechargeable NiMH cells with a capacity of 2500mAH, giving typically
24 hours use when fully charged. Charging is done using the AC adaptor supplied, see below.
The Bat annunciator shows in the top right-hand corner of the display when the instrument is
operating from its internal battery; this changes to Lo Bat when approximately 10% of battery
life remains. During battery operation the instrument is turned on and off with alternate presses
of the OPERATE key.
USB Power
The instrument can also be powered from a PC’s host port, even if the instrument’s battery is flat;
the battery will not, however, be recharged from USB power. Connect the instrument’s rear panel
USB connector to a PC via a standard USB cable; the Windows’ plug and play function should
automatically recognise the addition of new hardware and, if this is the first time the connection
has been made, prompt for the location of a suitable driver. The disk supplied with the
instrument contains drivers for various versions of Windows; follow the PC’s on-screen prompts
to load the appropriate driver (there are two separate stages).
Note: If the plug and play function reports that a later version of the driver is already installed,
keep the later version; the TF960 will operate satisfactorily with the later version.
The instrument will only be powered via its USB port if the connection is properly enumerated, so
it is not possible to use adaptors which only provide DC power through a USB connector. USB
power takes priority over battery power to preserve battery charge; the Bat or Lo Bat
annunciator goes off to indicate this.
If the instrument is off when the USB connection is enumerated then the instrument will
automatically power on and, when the USB power is removed, it will power off again. If the
instrument is running on battery when the USB connection is enumerated then USB power will
take precedence in powering the instrument and, when the USB connection is removed, the
instrument will continue to operate from the battery. The instrument can be turned off and on with
USB power connected using the OPERATE key. USB power can be used without the USB
connection being used for remote control.