Arc Machines 207 - Manual (Page 24)

MODEL 207A AND 207A-1
OPERATION MANUAL
Doc. No. 740044
Rev F
SECTION IV - SYSTEM FUNCTIONS
4.2 WELD LIBRARY AND WELD DESCRIPTION
Each weld schedule programmed into the system memory is identified and
displayed (when selected) with the following information:
1. # = Individual WELD SCHEDULE NUMBER from 001 to 100.
2. OD = Outside diameter in inches or mm of the weld.
3. WALL = Wall thickness in inches or mm of the weld.
4. TYPE = Uses abbreviations to identify the type of weld the schedule is for
(see section 4.9 for list).
5. MAT = Uses abbreviations to identify the base material the schedule is for
(see section 4.9 for list).
6. QTY = Indicates the number of times this weld schedule has been used since
last reset.
4.3 WELD SEQUENCE - Although the M-207A can be used as a manual welding
power source, it is primarily intended to follow an automatic SEQUENCE.
After a weld schedule is selected and the weld is setup, the SEQUENCE will be
manually started by the operator and the following events will occur automatically
(see figure 5 for the timing chart):
1. EVENT 1: PREPURGE - Welding gas will start to flow (for the entire weld)
from the gas source (user supplied) through the power supply to the weld
head. Complete gas coverage should be obtained before the arc is struck.
How long it flows before the arc is struck is called the PREPURGE TIME.
Minimum programmable time is 10 seconds.
2. EVENT 2: ARC START - When PREPURGE time is complete a high
frequency pulse will be generated to establish an arc between the electrode
and the weld joint.
3. EVENT 3: LEVEL 1 TIME, START LEVEL, UPSLOPE, TRAVEL START
DELAY - When the arc starts the following functions all start at the same time:
1. LEVEL 1 TIME - When the arc is established all weld functions are
considered to be in LEVEL 1. The LEVEL 1 Timer will start to count
and the M-207A will stay in LEVEL 1 until this time is complete.
2. WELD CURRENT START LEVEL - As the arc is established the
weld current will jump to a small value. This current is used to stabilize
the arc and is called the START LEVEL. Its value is adjustable and
may need to be changed depending on certain conditions.
4.3