Arc Machines 207 - Manual (Page 27)

MODEL 207A AND 207A-1
OPERATION MANUAL
Doc. No. 740044
Rev F
SECTION IV - SYSTEM FUNCTIONS
4.3 WELD SEQUENCE
4. EVENT 4: FULL LEVEL FUNCTIONS -
NOTE
Travel direction is programmable CLOCKWISE or COUNTER-
CLOCKWISE. After the TRAVEL START DELAY the arc will
rotate in the programmed direction. The direction is not programmable by
LEVELS. It will rotate the arc in the same direction for the entire WELD
SEQUENCE.
5. EVENT 5: LEVEL 2 TO LAST PROGRAMMED LEVEL - As the arc is
rotated around the weld it is usually necessary to program changes in the
current, pulse times, modes and rotation speed. These changes are called
LEVELS and up to 100 can be programmed for each sequence. Each
LEVEL contains the same functions and options as EVENT 4. Each
LEVEL TIME determines the duration of that level.
6. EVENT 6: DOWNSLOPE - When the last programmed LEVEL is
complete the WELD SEQUENCE will begin the process of stopping. To
avoid cratering and cracking of the weld the current needs to be reduced
slowly. The last LEVEL PRIMARY-AMP value and BACKGROUND-
AMP value (if pulsed)will start to decrease towards 0. This time is called
DOWNSLOPE and is programmable.
7. EVENT 7: POSTPURGE - At the end of DOWNSLOPE, when the current
is less than 3 amperes, the arc will go out. All functions except gas flow
will stop. The gas should not be stopped until the weld and electrode are
cooled enough to prevent oxidation. How long the gas continues to flow is
programmable and is called the POSTPURGE TIME.
8. EVENT 8: RETURN TO HOME AND RESET - When POSTPURGE is
complete the gas will shut off. The M-9 welding head rotor will usually not
be in the proper position for head removal from the weld. When the gas shuts
off the rotor will return to the open (home) position and the weld head
can be removed from the weld. The system will then reset and be ready to
make another weld sequence.
4.6