Miller Electric OM-842 - Manuel (Page 24)

OM-842 Page 20
Ref. SB-139 983
In this mode, a single momentary
closure of the Start/Increase push
button starts the sequence. The pro-
gram continues through the pro-
grammed sequence of events until
weld/peak current. The operator
presses the Start/Increase push but-
ton to signal the end of weld/peak
current, at which time final slope
starts.
The weld amperage cannot be in-
creased or decreased once the se-
quence has started, and the Stop
push button is not functional. Post-
flow starts if the arc is manually
broken.
A: Momentary closure of Start/Increase push button starts sequence.
B: Momentary closure of Start/Increase push button ends weld/peak cur-
rent.
Preflow: Time programmed/Volume set by gas meter.
Start Level (Not Shown): Time & level programmed.
Initial Current: Time & level programmed.
Initial Slope: Time programmed/Slope calculated by microprocessor
control.
Weld/Peak Current: Time undefined/Level programmed.
Final Slope: Time programmed/Slope calculated by microprocessor
control.
Final Current: Time & level programmed.
Postflow: Time programmed/Volume set by gas meter.
Weld/peak current cannot be increased or decreased during welding.
Stop push button is not functional throughout sequence.
A
Initial
Current
Weld/Peak
Current Initial
Slope
Final
Slope
Final
Current
Preflow Postflow
B
Figure 4-5. Semi-Automatic 5 Mode Sequence
C. Manual GTAW Mode Sequence
Ref. SB-139 983
A Manual GTAW program requires
the operator to perform most of the
control of the welding process. This
is carried out through the use of a re-
mote control providing contactor and
amperage control (not the Remote
Pendant). High frequency is avail-
able for non-contact weld starts.
Preflow starts when the remote con-
tactor control is closed. Following
arc ignition, the weld sequence en-
ters initial current. Once initial cur-
rent starts, the operator controls the
output level through the use of the
remote amperage control. The maxi-
mum output that can be commanded
is defined when the program is
created. The minimum value that
can be commanded is the defined
initial current level. Postflow starts
when the remote contactor control is
opened.
A: Closure of remote contactor control starts sequence.
B: Arc ignition starts initial current.
C: Opening of remote contactor control starts postflow.
Preflow: Time programmed/Volume set by gas meter.
Start Level (Not Shown): Time & level programmed.
Initial Current: Time undefined/Level programmed.
Initial Slope:
Weld/Peak Current:
Final Slope:
Final Current:
Postflow: Time programmed/Volume set by gas meter.
Remote Pendant not used.
Weld/peak current can be increased or decreased during welding.
A
Initial
Current
Weld/Peak
Current Initial
Slope
Final
Slope
Final
Current
Preflow Postflow
B
C
Not separate steps.
Current level controlled by remote
amperage control.
D. SMAW Mode
A program entered in the SMAW mode does not follow the weld sequence shown in Section 4-2. On/Off control of the welding power
source contactor is accomplished through a remote contactor control, and arc initiation and extinguishing are done manually. Weld
output can be controlled remotely or kept at a defined level, depending on programmed parameters. If remote control is used, the
maximum output that can be commanded is defined when the program is created. The minimum is the minimum output the welding
power source is capable of.