Lincoln Electric POWER FEED 25M NNS Operator's Manual page 30

POWER FEED™ 25M NNS
2-Step Trigger
Example 3: 2-Step Trigger: Customized Arc Start, Crater and Arc End
Aluminum is an example of where start, crater and burnback are commonly used to improve welding performance.
For this sequence,
PREFLOW:
Shielding gas begins to flow immediately when the gun trigger is pulled.
RUN-IN:
After preflow time expires, the power source regulates to the start output and wire is advanced towards the
work piece at the Run-In WFS. If an arc is not established within 2.0 seconds, the power source output and
wire feed speed skips to the weld settings.
START & UPSLOPE:
Once the wire touches the work and an arc is established, both the machine output and the wire feed speed
ramp to the weld settings throughout the start time. The time period of ramping from the start settings to the
weld settings is called UPSLOPE.
WELD:
After upslope, the power source output and the wire feed speed continue at the weld settings.
BURNBACK:
After the crater time expires, the wire feed speed is turned OFF and the machine output continues for the burn-
back time.
POSTFLOW:
Next, the machine output is turned OFF and shielding gas continues until the post flow timer expires.
2-Step trigger: Special considerations
The weld sequence response depends upon when the trigger is pulled and released and whether or not START or CRATER are active.
An example sequence:
Pull the trigger to start feed of wire. When arc is established the sequencer will begin START/UPSLOPE. If trigger is released during
UPSLOPE and CRATER/DOWNSLOPE is active, the machine will begin CRATER/DOWNSLOPE and sloping down over the CRATER time,
regardless of when the trigger release occurred.
If the CRATER is disabled and the trigger is released during START/UPSLOPE, the sequencer will move to the BURNBACK state to end
the weld.
B 15
OPERATION