Not separate steps.
Current level controlled by remote amperage control.

Weld/Peak

Initial Current B Final

Slope Slope

Initial

Final

Current

Current

Preflow

Postflow

A

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.

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.

Ref. SB-139 983

Figure 4-5. Semi-Automatic 5 Mode Sequence

C. Manual GTAW Mode Sequence

 

Initial

Weld/Peak

Final

 

Current

 

Slope

 

Slope

 

Initial

 

Final

B

Current

 

Current

 

 

 

Preflow

 

 

C Postflow

A

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 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.

Ref. SB-139 983

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.

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Miller Electric OM-842 manual Smaw Mode, Weld/Peak Initial Current B Final Slope Slope, Preflow Postflow

OM-842 specifications

The Miller Electric OM-842 is a versatile and powerful multi-process welding machine designed for professional welders who demand efficiency and reliability on the job. This industrial-grade welder is capable of handling various welding processes, including MIG, TIG, stick, and flux-cored welding, making it an ideal choice for a wide range of applications.

One of the standout features of the OM-842 is its robust output capability. With a maximum output of 400 amps, it can tackle thick materials with ease while maintaining exceptional arc stability. This output range allows for adaptability in different welding scenarios, whether working on heavy fabrication projects or lighter home repairs.

The OM-842 is also equipped with advanced inverter technology. This technology enhances the machine's efficiency and reduces energy consumption. Inverter machines are known for their lightweight design compared to traditional transformer welders, which makes the OM-842 more portable and easier to transport between job sites.

User-friendliness is paramount in the design of the OM-842. Its intuitive control panel features a digital display that provides real-time information on parameters such as voltage and amperage. This allows users to make quick and precise adjustments on the fly, enhancing productivity and ensuring optimal welding results.

Additionally, the OM-842 offers sophisticated weld control features, such as Auto-Set, which simplifies the setup process for beginners and experienced users alike. This technology automatically selects optimal parameters based on the material type and thickness, minimizing trial and error during welding.

The machine also includes a durable and rugged design, suitable for tough working conditions. The protective case and high-quality components ensure longevity and reliability even in adverse environments.

Safety is another critical aspect of the OM-842, with features such as over-temperature protection and a built-in fan to prevent overheating during extended use.

With its powerful performance, advanced technology, and robust design, the Miller Electric OM-842 stands out as an exceptional choice for welders seeking reliability and versatility in their welding operations, ultimately creating high-quality welds across various applications. Whether in a shop or on a construction site, the OM-842 is engineered to deliver outstanding results every time.