Lincoln Electric Saf-Fro PRESTOTIG 315DC Manuel D'utilisation page 13

6 CRATER
This function controls the final current value after
the Downslope. For an explanation of the Crater
operation, refer to the trigger sequences explained
below.
7 POSTFLOW
In the TIG welding modes, this function controls the
shielding gas Postflow time. In Stick welding mode,
this is not used.
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.
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:
Action
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.
After the arc is started the output current will be
increased at a controlled rate, or upslope time, until
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Visualization
10
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.
2. Release the TIG torch trigger to stop welding. The
machine will now decrease the output current at a
controlled rate, or downslope time, until the Crater
current is reached and the output of the machine is
turned OFF.
After the arc is turned OFF, the gas valve will
remain open to continue the flow of the shielding
gas to the hot electrode and work piece.
As shown above, it is possible to press and hold the TIG
torch trigger a second time during downslope to end the
downslope function and maintain the output current at
the Crater current. When the TIG torch trigger is
released the output will turn OFF and the postflow time
will start. This operation sequence, 2-step with restart
disabled, is the default setting from the factory.
2-Step Trigger Sequence with Restart Option
To select 2-Step with restart sequence:
Action
+
See "Setup menu" section below
Press several times until the LED above lights up
If the 2-step restart option is enabled from the setup
menu the following sequence will occur:
Visualization
then:
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