Lincoln Electric V160-S Service Manual page 42

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4-Step Sequence
Note: 4-Step works with Arc Start Switch only. Amptrol™
type devices will not work properly and should not
be used. The Arc Start Switch's actuator is also
referred to as the "Tig torch trigger" in the following
sequence.
1. Press and hold the Arc Start Switch to start the
sequence. The machine will open the gas valve to start
the flow of the shielding gas. After 0.5 second preflow
time to purge air from the torch hose, the output of the
machine is turned ON. At this time the arc can be start-
ed. After the arc is started the output current will be at
the Start/Finish current. This condition can be main-
tained as long or as short as necessary.
If the Start/Finish current is not necessary, do not hold
the TIG torch trigger as described at the beginning of
this step. Instead, quickly press and release the trigger.
In this condition, the machine will automatically pass
from Step 1 to Step 2 when the arc is started.
2. Release the TIG torch trigger to start the main part of
the weld.
The output current will increase to the welding current.
The time for this increase or upslope is presettable.
The default is 0.5 seconds.
3. Press and hold the TIG torch trigger when the main part
of the weld is complete.
The machine will now decrease the output current at a
controlled rate or downslope time, until the Start/Finish
current is reached. The downslope time is adjusted by
the Downslope Parameter. This Start/Finish current
can be maintained as long or as short as necessary.
4. Release the TIG torch trigger.
The output current of the machine will turn OFF and the
gas valve will remain open to continue the flow of the
shielding gas. The duration of this postflow time is
adjusted by the Postflow control knob. This operation is
shown in (4 step diagram 1).
4 Step Diagram 1
OPERATION
Possible variations of this standard sequence are
shown below. It is possible to press and hold the TIG
torch trigger another time to end the downslope time
and maintain the output current at the Start/Finish cur-
rent. When the TIG torch trigger is released the output
will turn OFF and postflow will begin. This operation
shown in (4 step diagram 2).
V160-S & -T
4 Step Diagram 2
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