Miller Electric OM-842 - Manuel (Page 33)

OM-842 Page 29
8. Press Right/Increase. The microprocessor control will
enter the Ready condition.
9. In the Ready condition the microprocessor control is
ready to have another program entered or to execute a
program. For information on executing a program, see
Section 6.
5-4. Manual GTAW Mode
If needed, see Section 5-1B for
information on selecting and defining
a parameter.
NOTE
Weld output options, such as the use
of pulsing, high frequency, and ac or
dc output, affect how a program is
entered in the Manual GTAW mode.
Be sure to follow all applicable steps,
and only the applicable steps, as
determined by the selected options.
NOTE
A. Procedure Up To Pulse Mode Selection
1. Turn on welding power source, if applicable.
2. Place the Mode Selector switch in the Manual GTAW
position.
3. Place the Program/Run/Reset keyed switch in the Re-
set position, and then in the Program position. The
initial displays will be shown.
4. When the repeating displays (explained in Section
5-1F) are shown, press Right/Increase.
If the Process Selector switch is in the ac output posi-
tion, go to Step 5. If the Process Selector switch is in a
dc output position, go to Step 8.
5. The display shows:
# 0 X B A L A N C E C O N T R O L
E N = X X % E P = X X %
6. If applicable, define the program number (see Section
5-1C). Define the electrode negative value for the ac
output square wave (see Section 4-3) as desired.
The range for percentage of waveform in electrode
negative is 46% to 68%, in increments of 2%.
7. Press Right/Increase, and go to Step 8.
8. The display shows:
H I G H F R E Q U E N C Y
> X X X X X X X X X <
9. Press Parameter Select to display the desired choice.
If the Process Selector switch is in the ac output posi-
tion, the choices are Start Only high frequency or
Continuous high frequency.
If the Process Selector switch is in a dc output position,
the choices are Start Only high frequency or Disabled
high frequency.
10. When the desired choice is shown, press Right/In-
crease to advance to the next display. The display
shows:
# 0 X P R E F L O W
T I M E = X X .X
11. If applicable, define the program number (see Section
5-1C). Define the shielding gas preflow time as desired.
The range for preflow is 0.0 to 25.0 seconds, in incre-
ments of 0.1 seconds.
12. Press Right/Increase, and the display shows:
# 0 X S T A R T L E V E L
T I M E = .X X X A M P S = X X X .X
13. Define the start level time and amperage as desired.
When properly used, start level eases arc starting by
allowing the use of an amperage value that is higher
than initial amperage for a short length of time.
The range for start level time is 0.0 to 15.0 seconds, in
increments of 0.1 seconds. The range for start level
amperage varies from 2.0 to 400 amperes, in incre-
ments of 1.0 amperes.
14. Press Right/Increase, and the display shows:
* * P U L S E M O D E I S * *
> X X <
15. Pressing Parameter Select toggles the display be-
tween pulse mode On and pulse mode Off. Three
possibilities exist at this point, as follows:
Pulse mode On is desired and pulses are to be defined
as time spent in peak current and background current
(see Step 16).
Pulse mode On is desired and pulses are to be defined
as a frequency, with peak current defined as a percent-
age of the total period (see Step 16).
Pulse mode Off is desired (see Step 17).
16. To define pulse mode On, proceed as follows:
a. Be sure the desired means of defining pulse mode
has been selected according to Section 2-4.
b. Use the Parameter Select push button to select
pulse mode On, and press Right/Increase to ad-
vance to the next display while ”On” is displayed.
c. If pulses are being defined as time values, go to
Section 5-4B.
If pulses are being defined as a frequency, go to
Section 5-4C.
17. To define pulse mode Off, proceed as follows:
a. Use the Parameter Select push button to select
pulse mode Off, and press Right/Increase while
”Off” is displayed. The display shows: