Lincoln Electric POWER FEED 25M Service Manual page 45

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P.8 TIG Gas Control (Two Settings)
1. "Valve (manual)", the internal solenoid will not
actuate while TIG welding, gas flow is manually
controlled by an external valve.
2. "Solenoid (auto)", the internal gas solenoid will
turn on and off automatically while TIG welding as
follows:
• Preflow time will not be accessible from the MSP4.
• Postflow time will be available in the MSP4 "End
Options" and have a range of OFF to 10.0 sec-
onds.
• The postflow time value is maintained when
switching between MIG and TIG modes.
• When machine output on/off is controlled via the
right encoder, gas flow will not start until the tung-
sten touches, the work piece, gas flow will stop
after the postflow time when the arc is broken.
• When machine output on/off is controlled via an
arc start switch or foot Amptrol, gas will begin flow-
ing when the output is turned on and stop flowing
after the postflow period after the output is turned
off.
P.11 Set Timers
This menu is used to adjust timer values for
Upslope, Downslope and Restrike. Press the
right button to enter the Set Timer menu.
Rotate the knob to select the timer to adjust
and then press the right button. Adjust the
value of the timer by rotating the knob. Press
the left MSP4 button to set the value and exit.
Continue to adjust other timers as necessary,
and then press the left button to exit the Set
Timer menu.
P.12 Travel Options
This menu is used to change the travel options
for a travel carriage, including starting and
ending functions. The right MSP4 button to
enter the Travel Options menu and rotate the
encoder to select either starting or ending
options. Press the right MSP4 button to select
the option. Press the left MSP4 button to set
the value and exit. Rotate the encoder to select
other options, or press the left MSP4 button to
exit the menu.
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OPERATION
POWER FEED® 25M
P.13 Adjust Arc Force
Use this menu to adjust Arc Force values for
Start, Weld and Crater. Press the right MSP4
button to enter the menu and rotate the knob
to choose either Start, Weld or Crater. Press
the right MSP4 button and then rotate the knob
to the desired value. Press the left MSP4 but-
ton to set the value and exit. Continue to
adjust Arc Force for other states, and then
press the left MSP4 button to exit the menu.
P.80 Sense From Studs (two settings)
1. "False", the voltage sense lead is automat-
ically selected based on the DIP switch con-
figuration and the selected weld mode. This
is the default value that is used every time
the machine is powered up. Note that set-
ting P.80 to "False" does not preclude volt-
age sensing from the studs if studs sensing
is specified by the selected weld mode (for
example stick and TIG weld modes will still
sense voltage at the studs).
2. "True", voltage sensing is forced to "studs"
regardless of the DIP switch configuration
and selected weld mode. Setting P.80 to
"True" should only be done for trou-
bleshooting purposes. P.80 will automatical-
ly be set back to "False" the next time the
equipment is powered up or can be manual-
ly changed back to "False" via the setup
menu.
In order to control the welding arc, the power
source continually monitors arc current and
arc voltage. Arc current is measured internal
to the power source. Arc voltage can be mea-
sured as follows:
• Voltage internal to the power source ("studs")
• Voltage at the wire feeder ("67" lead)
• Voltage at a user-wired sense lead ("21"
lead)
Remote voltage sensing (anything other than
"studs") is used to obtain a more accurate volt-
age measurement since the sense lead is
closer to the arc. Remote voltage sensing can
involve external wiring and DIP switch configu-
ration, there is a potential for incorrect voltage
measurement which can lead to poor arc con-
trol or wire burn back.
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