Lincoln Electric SQUARE WAVE TIG 355 Service Manual page 26

B-10
• ARC ESTABLISHED LED goes on when the arc
is fully established and goes out if the arc goes
out.
• START LED is on from the time the arc is estab-
lished until current begins to go up (soft start) or
down (hot start). Note that the Start LED is off
during upslope if a soft start is used.
• PEAK LED goes on after the Start period. If the
Pulse switch is on, the Peak LED goes off during
the Background periods.
Background LED will alternate when pulsing.
• BACKGROUND LED
Background (low pulse) period of pulsing.
• CRATER FILL LED is on during the Fade-Out
downslope and final current periods.
OPERATION
NOTE: An LED will light in response to the control cir-
The Peak LED and
The Status Indicator LEDs are useful for understanding
which functions are active during a weld sequence and
is on during the for how long. They are useful for setting times of the
controls on the Function Panel. See Figure B.2.
The Status Indicator LED circuit board includes a
receptacle for plugging in the circuit board included
with the Optional Interface Kit.
SQUARE WAVE TIG 355
cuit command, even if other components do
not work. For example, if the gas supply is
turned off or the gas solenoid valve malfunc-
tions or the fuse is blown, the gas will not flow
even though the Gas and Water LED lights up.
Another example is the High Frequency LED
which can light, yet there will not be high fre-
quency due to a blown fuse or defective high
frequency circuit or spark gaps set too large.
B-10