Lincoln Electric ASPECT 300 Operator's Manual page 16

HF TIG
When the mode pushbutton is in HF TIG position, the
machine is ready for HF TIG welding. During the HF
TIG mode, the TIG arc is started by HF without pressing
the electrode on the work piece.
starting the TIG arc will remain on for 3 seconds; if the
arc is not started in this time limit, the trigger sequence
must be restarted.
NOTE: The HF start strength is adjusted to the
tungstensize and type, which can be selected in menu
GTAW.
AC Tig Welding
To start AC Tig welding process:
1.) Set polarity
2.) To select AC Tig welding:
Process
Press MODE several times until the LED above lights up
2T led is turned on for default.
Ac wave shape section is available. About Lift and Tig
starting see section above.
Tig Welding Sequences
During no welding operation at each pressure of SEL
push button, it's possible to step through all sequencer
and set parameters.
During welding the Sel pushbutton is enabled for the
following functions:

Output current

Only if Pulse Function is active: is possible operates
on the values of Duty (%), Frequency (Hz) and
Background current (A).
The new parameter value is automatically saved.
English
The HF used for
Visualization
Lift
HF
14
TIG Trigger Sequences
TIG welding can be done in either the 2-step or 4-step
mode. The specific sequences of operation for the
trigger modes are explained below.
Legenda of the symbols used:
Torch Pushbutton
Output Current
Gas Pre-flow
Gas
Gas Post-flow
2-Step Trigger Sequence
To select 2-Step sequence:
Output
Press several times until the LED above lights up
With the 2-step trigger mode and a TIG welding mode
selected, the following welding sequence will occur.
1. Press and hold the TIG torch trigger to start the
sequence. The machine will open the gas valve to
start the flow of the shielding gas. After the preflow
time, to purge air from the torch hose, the output of
the machine is turned ON. At this time the arc is
started according to the selected welding mode. The
initial current is set to 25A for LIFT starting (starting
current parameter is disabled in the sequencer) or
set according to the Starting current parameter for
HF starting. After the arc is started the output
current will be increased at a controlled rate, or
upslope time, until the Welding current is reached.
If the torch trigger is released during the upslope
time the arc will stop immediately and the output of
the machine is turned OFF.
Visualization
English