Arc Machines 227 - Manual (Page 30)

MODEL 227
OPERATION MANUAL
Doc # 740063 Rev E
SECTION IV - SYSTEM FUNCTIONS
4.3 WELD SEQUENCE
2. EVENT 2: ARC START - When PREPURGE time is complete the M-227
will initiate an arc. The Arc Start MODE can be set to either RF or TOUCH.
In RF mode a high frequency pulse will be generated to establish an arc
between the electrode and the weld joint. In TOUCH mode the AVC will
perform a TOUCH START and initiate the arc (can only be used with
Weld Heads with an AVC function).
3. EVENT 3: LEVEL 1 TIME, START LEVEL, UPSLOPE, TRAVEL and
WIRE START DELAY, AVC START DELAY and OSC UPSLOPE -
When the arc is established 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. If the TIMER MODE is in AUTO the
LEVEL 1 Timer will start to count and the M-227 will stay in LEVEL 1
until this time is complete. If the TIMER MODE is set to MANUAL the
system will still be in LEVEL 1 but the timer will not be counting and
the system will stay in LEVEL 1 until the operator manually advances or
ends the sequence.
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 programmable and
may need to be changed depending on certain conditions. However, it
is not a multi-level function and it is only used to help initiate the arc.
3. WELD CURRENT UPSLOPE - Sometimes it may be necessary to raise
the weld current to full value slowly. This is called UPSLOPE. When
the arc is established the weld current will start to rise to the PRIMARY
and BACKGROUND (if pulsed) value programmed in LEVEL 1. The
time it takes to rise to full value is the UPSLOPE TIME.
4. PRIMARY and BACKGROUND PULSE TIMES - When the arc is
established and the LEVEL 1 PULSE MODE is programmed to the ON
position, the weld current will be pulsing between the PRIMARY and
BACKGROUND functions at the rate set by the Level 1 PULSE
TIMES.
5. TRAVEL START DELAY - Rotation of the arc should not occur in
most cases, until full penetration of the weld has been achieved. When
the arc is established the TRAVEL START DELAY time will begin to
count. When this programmable period of time is complete the weld
head will start to rotate the arc.
4.4