View Full Version :

Functions of the control panel knobs on multi process unit

01-14-2009, 11:01 AM
I was hoping we could all discuss and figure out what all the knobs do and when they should be used and I will edit this first post so all the info is in one topic in the very first post in that topic for easy reference and seachabillity. please post corrections and additions: I'm just getting this started.

Arc welding:
AC/DC switch: sets machine in AC current or DC current mode
Square wave/constant wave form?: I assume you want square wave for AC and constant wave form? for DC
peak current: allows you to adjust amperage and will be displayed on digital read out
Basic Current: Does this have any effect on stick?
Arc force: Adjusts the voltage increasing this will create a more forcefull arc will allow for greater electrode to work piece distance and deeper penetration.
Machine can be used for both DCEP and DCEN

TIG welding: (added by Gadget)
Upslope and downslope time: down control the speed the current reaches the set level at the start of the arc and how quickly it tapers off at the end of the cut.
Clean Width: This determines the AC current cycle for welding aluminum, a wider width cleans better but does not penetrate as much. More of the AC cycle going to the negative electrode. Narrower puts more of the AC cycle in the positive cycle penetrating more.
Post Gas[/b:] Determines how long the gas continues to flow after the arc has stopped, longer keeps metal from oxidizing.
[b] Pulse Frequency: Determines the frequency of the AC pulse for welding aluminum, I think faster pulse makes a cleaner weld, slower penetrates more.
basic current: used w/o the foot pedal will limit the AMP to that % of the max out put of the machine use in conjunction with the upslope and down slope dials when using the torch only w/o the foot pedal.
2T/4T: With 2T the arc starts and stops with the logical pedal movement. With 4T you depress the pedal to start and it continues until you let off the pedal and press and release the pedal again.
Arc Force: I have found that when using TIG on thin metal reducing the arc force reduces the chance of blowing through the metal. Again it reduces the voltage not the current.
foot pedal dial: limits the max amperage of the machine EX. if you machine is set to 200A, you are welding something and wish not to go over 100amps, you can turn you dial on the foot pedal half way.
If I am wrong on any of these don't hesitate to let me know. Gadget

Peak current: This is the cutting current and is the only thing that should be adjusted in plasma (must be DC mode, 2T, Square wave off) . all other dials need to be set to 0. The post gas still operates in the same manner as in TIG but you are using compressed air for plasma. (So if you have the post gas flow set to 10s the air will continue to flow through the torch for 10s AFTER releasing the trigger-there is no need for this and it seems as though you cann't re initiate a arc until the post flow stops)

01-14-2009, 07:30 PM
You are " Da man" :lol:
This is exactly what we need!
I have just begun to atempt to tig.. I need to know how the " Peak current" affects the machine in Tig ( without foot pedal and wITH foot pedal)
as well as the relationship of the peak current on the machine and the knob on the foot pedal. i have an idea how it works, but my "FUZZY LOGIC" :roll: could well be wrong so I would just like a clear and corect answer to my quest. For now I am just interested in tig on steel ( DC mode only. i don't want to confuse the issue with AC mode for Alum) so.... to tig steel what knobs get set and how do they get set...WITH FOOT PEDAL and WITHOUT FOOT PEDAL
thanks to anyone who can clearly explain the settings.. :)

01-14-2009, 08:46 PM
My pedal does not have a knob but I was told all current settings should be set to 0 when using the pedal. They are overridden by the pedal.
Hope this helps,

01-14-2009, 09:24 PM
I think I noticed that I could set the amperage to the max I wanted and the foot pedal would modulate up to that set max. I was my first time so I don't have a really good sense between operator technique variations on the arc and setting changes.

post if I made any errors or any addittions and I will edit the initial post to correct it.

a few of the things I would like to know:
how peak current changes the carractorisitc of the amperage
what the dial on the foot pedal does
how to use the two pulse dials on is pulse frequency the other probably % decrease of the amperage of the pulse.
I also just got off the phone with Jesse at longevity about some problems I've had with the plasma and he told me that the other dials other than peak current are still active in plasma mode and need to be set to 0

01-15-2009, 01:47 AM

Your pedal ranges the max amps on the machine. Example, you are welding something and wish not to go over 100amps, you can turn you dial half way. As far as the plasma, only the peak current is what controls the plasma cutter, but your machine should be at 2t if applicable, dc, pulse off and all the other knobs turned down. Having the post flow or others on may pass air constantly though your torch.

Also, for pilot torches check the consumables as they can interfere with a good arc or prevent an arc. Make sure they are tight.


01-15-2009, 10:48 AM
thanks, I edited you responses into my original post

01-15-2009, 02:31 PM
I just talked to Simon about pulse functions I'm not quite clear on what the pulse duty controls (does it change the amerage or voltage or both). but what I could understand from the conversation it it will increase the power of the arc. simon said start with it turned 1/4-1/2 and adjust from there. On thinner material and you are burning through or out of position and your puddle drops out turn it down also simon reccomended turning the pule frequency down. Since I'm not too clear on this and have not messed around with the pulse functions yet I wanted to get some input before I put it in the first post.

I also learned how to use the basic current dial while TIG and added that to the post.

01-15-2009, 03:34 PM

Sorry I was not clear on the phone... let me try again.

Basic current is background current not the peak or actual current and it is used for the low side of the pulse. 1/2, 1/4 or even 1/10 of the peak current.

Arc force is supposed to control the amount of arc on the stick, but it also in our machines puts out ohms on the tig side. Basically, i want to go ahead and start at 1/4 of the way.


01-15-2009, 04:29 PM
I am moer confused than ever!!

I think that we need is a spread sheet to explain the switch settings and what they do in the different welding functions.
I have start one for the 160P, I am not sure that I can post the sheet, but I will try.
Please let me know of all errors!

This is not the final setting sheet, please help

01-15-2009, 07:44 PM

You want square wave selected for both AC stick and AC TIG

01-15-2009, 07:48 PM
I like the spread sheet thing, but what do the A and B signify under Square wave ? ( i asume that is square wave)

01-15-2009, 09:58 PM
vault wrote,

You want square wave selected for both AC stick and AC TIG

This is not the case on my welder. I am not sure, the amount of time I have used it is limited due to the cold welder.
I am not sure about the foot switch either.
This needs to be clairified by Longevity.

The thought is that a cheet sheet like I am showing would be helpfull to all, but the sheet must be correct and a sheet for each welder is needed!


02-12-2009, 09:06 PM
Thanks for getting the "KNOB ID" subject started. I have a LS-200P multi-purpose unit with pilot torch.

Your input has been extremely helpful to me. However it appears no solution presently exist to identify "Control Panel Knob" functionality on Longevity units. I feel some unit failures could have resulted from lack of manufacturer operating instructions. These machines are too complex and expensive for experimentation.

I'm on my third multi-purpose unit and not sure if it is my actions due to lack of factory operating instructions or product quality. Simon has been cooperative and professional to replace my units, however, lost time and paying cross country shipping charges has made me question my purchase.

I bought a screwdriver from Sears last week and it had more operating instructions with it than my Longevity LS-200P.

I like the "Spread Sheet" approach, however we need a different sheet for each unit, as most of you indicated. I would like to be cutting & welding, not experimenting with knobs and paying freight companies.

Overall your threads have been very helpful, but where do we go from here?

02-12-2009, 09:36 PM
I understand that Simon is working on a updated operation manuals for the multi-purpose units. I do not know of his progress or a completion date.


02-13-2009, 02:36 AM
Hi Guys,

I hired a professional company from LA to rewrite our manuals. I hope to have them on the site in 1 month. Please bear with us. We hear you loud and clear and will get you what you ask for.



02-26-2009, 10:18 AM
Great minds think alike....

I've created a spreadsheet too -- totally independently. So let's have some comments

I'm a mechanical engineer, so my life is in the details. I thought I'd use that focus to create a worksheet that gives the infrequent or rookie user the settings basics for running this machine in its various mode.

I have a Longevity WeldAll LS-200P and it seems to be identical to Everlast, Longevity, Riland USA, Maos Electric, Ramsond or Mitech models. I'm certainly not advocating for any specific brand (note I like my Longevity just fine) , I'm just trying to figure out the settings on my Super 200P. All the above models of 180P, 200P, and 250P have the same control panels and have identical "manuals" if you can call them that. What I'm looking for is to create a settings table to help rookie users such as myself learn to use these machines... thus increasing their popularity and building more support, parts, service, product knowledge, etc.

for others of you interested in geeky testing, there's a post by a guy named Hildstrom on the Everlast Super 250P over on their forum. Quite interesting info there too.

Also if others have tabular data that would help with power settings or other configuration data, I thought I'd paste that into the grey corner area once I get some info.

Well, it seems the site won't accept Excel Spreadsheets, nor PDFs.... so I've pasted it as an image. If you want the spreadsheet, PM me I guess

Many thanks in advance to any/all input.

To the hosts of this Longevity site. I'm glad to allow you to distribute/use this document as you see appropriate to your user base once it has been properly vetted.

--Dan (2fatdogs)

02-26-2009, 10:52 AM

Looks great. Please send me a copy if you would.

02-26-2009, 02:55 PM
Got it Dan, Thanks!

03-29-2009, 01:49 AM
Guys.. Where can i get that spreadsheet??


03-29-2009, 10:12 AM
if you want the first spread sheet(Pictured Knobs) PM me your email address

If you want the second spread sheet PM 2fatdogs and i am sure he will help.


05-02-2009, 06:17 PM
Me too please!


Looks great. Please send me a copy if you would.

05-02-2009, 07:15 PM
Great minds think alike....

I've created a spreadsheet too -- totally independently. So let's have some comments

Well, it seems the site won't accept Excel Spreadsheets, nor PDFs.... so I've pasted it as an image. If you want the spreadsheet, PM me I guess

Many thanks in advance to any/all input.

To the hosts of this Longevity site. I'm glad to allow you to distribute/use this document as you see appropriate to your user base once it has been properly vetted.

--Dan (2fatdogs)

Dan, If you want it posted here send it to me and I will convert it to a JPEG and post it here for all. If that is not possible, I could enable spreadsheets here but JPEG would probably be best. Send me a PM for email information.

08-27-2009, 08:25 PM
ok the pulse duty is probally the amount of time the pulse on on the high end versus the low end. any other questions i would be more then happy to try to help.

09-12-2009, 06:34 AM
I believe you do need some post-flow during plasma cutting to cool the torch, probably around 5 seconds.

09-12-2009, 10:29 AM
Longevity WeldAll LS-200P

Front Panel

Power Lamp This light illuminates while the unit is powered on.

O.C. Over Current/Overheat lamp illuminates when the duty cycle has been exceeded or the machine has overheated due to improper ventilation. Discontinue use until lamp goes out. Allow the fan to continue to run. Once lamp goes out, you may resume using the unit.

Digital Display. The display posts the approximate welding amps.

Three Position Function Switch. Stick, TIG, Plasma.

AC/DC Switch. Use AC for Aluminum and Magnesium, DC for all other weldable metals and plasma cutting.

Basic Current. This is the primary AC & DC amperage control. Welding amperage is set using this control in the non-pulse mode. In the TIG pulse mode this knob sets the base current (low) amperage. For TIG pulse welding, first set the Peak Current to 0, then set the desired Basic Current (low amperage) using this knob. The digital display will show the amp setting. Next use the Peak Current control to set the high amperage of the high pulse cycle. As you turn the Peak Current control to the right the digital display will increase, showing your pulse peak amps.

Foot Control. The foot control overrides the Basic Current knob. When the Foot Control is pressed in the non-pulse mode the welding current is increased. In the pulse mode the foot control changes the base (low) amps, just as turning the Basic Current knob would do.

Pulse On/Off Switch (square wave/flat line) Enables pulsed TIG welding. Pulse welding allows fine control over the welding process. It gives the same effect as quickly moving the Basic Current knob back and forth between a low and high amp setting while welding but at a rate that would be impossible to do by hand. To set the high and low pulse currents, first set the Peak Current to 0, then adjust the Basic Current (low amperage), the digital display will show your amp setting. Next use the Peak Current control to set the high amperage of the high pulse cycle. As you turn the Peak Current control the digital display will increase, showing your pulse peak amperage.

Peak Current. Only active in pulse mode. Sets the peak (high) amperage of the pulse cycle. Select the Peak amperage with this control to achieve the maximum amperage requirements for the high pulse cycle. The amperage change will be reflected on the digital display.

Pulse Frequency. Only active in pulse mode. The TIG pulse frequency controls the number of pulse cycles per second (Hz). Changing the frequency sets the duration of each pulse cycle. The lower the frequency the longer the pulse. A higher frequency will shorten the pulse. This allows for fine control of heat input into the base metal.

Pulse Duty (pulse width). Only active in pulse mode. This TIG pulse control adjusts the relative amount of time that the pulse spends in the peak (high) current stage during a pulse cycle. For example a control knob setting of 90% or .9 will signal the pulse function of the machine to spend 90% of the time in the peak (high) current stage and 10% in the base (low) current stage of the pulse cycle. Note: The Pulse Duty does not control the overall length of the pulse. The pulse frequency sets the cycle length, thereby determining the overall length of each leg of the cycle. A higher pulse frequency will give a shorter pulse cycle.

Up Slope Time. TheUp Slope Time controls the time that the machine takes to ramp up the current from the start current to the normal welding current. This provides for excellent control over the welding puddle after it is developed and allows the operator to adjust manipulation techniques as the puddle warms up.

Down Slope Time. The Down Slope Time controls end cycle of the weld by slowly ramping down the welding current. As the end of the weld is reached, the down slope helps prevent weld cracking and hole formation in the crater.

Arc Force. This controls the dig of the arc. Primarily used for stick welding but does affect all modes. The dig is a term used to describe the intensity of the arc. It determines how hard the arc penetrates the metal when the arc is held short. This is an exceptionally helpful feature in MMA (SMAW--stick welding) operation. It helps hold the molten metal in place in out-of-position welds by providing a crisp, forceful arc. Or, it can provide a soft, buttery arc that easily washes the metal into the toes of the weld. This is a matter of operator preference. Rotating the knob clockwise increases dig. There are no recommended settings regarding this feature. Skill, operating styles and electrode selection are controlling variables that help determine the optimum setting of the arc force. Holding the arc close activates the arc force control and a increase of amps can be observed. With a little experimentation, the proper setting can be found for each task.

Clean Area Width (AC Balance). Only active in AC mode. This AC TIG & Stick control determines the amount of time the AC cycle spends in DCEN (Direct Current Electrode Negative -) or DCEP (DC Electrode Positive +). More DCEP is preferred for cleaning oxidation, particularly in aluminum. More DCEN is preferred for better penetration and faster travel speed. A 50% setting equalizes the time spent in both. A 30% setting is a good starting point for adjustment. A higher Clean Area Width will put more heat in the electrode, reduce this setting if you melt the electrode. Use 5356 filler rod for Aluminum.

Post Flow. This timer controls the flow of shielding gas after the TIG weld arc is terminated. Too little post flow time can cause weld contamination or torch overheating. During plasma cutting Post Flow allows for cooling air to flow after terminating the arc.

4T/2T Switch. This switch selects for control of the TIG weld cycle via the TIG torch trigger. In the 2T mode, simply touch and hold the trigger to start the arc and continue holding while welding. The machine will cycle automatically according to the settings selected on the machine. Release the trigger to finish. In the 4T mode each push of the trigger toggles between on and off (push and release trigger once to start, push and release once to stop welding).

09-12-2009, 10:41 AM
This is pretty much verbatim from the TIG instructions from Miller. They have a good site and used to have a downloadable manual detailing this as well as much other info, about 50 pages. It's a good resource for general welding info and general setting info along with detail on tungsten selection and gasses for various types of metals as well.

09-12-2009, 11:25 AM
LS-200P Operation
TIG Welding
(Tungsten Inert Gas - Gas Tungsten Arc Welding - GTAW)

AC TIG (Aluminum & Magnesium) - Select TIG, AC, desired amps using the Basic Current knob, Clean Area Width (start at around 30%), Post Flow 5-10 seconds, Pulse Mode off (flat line).

AC TIG Pulse (Aluminum & Magnesium) - Select TIG, AC, Pulse Mode on (square wave), set Peak Current to 0, then the desired low amperage using the Basic Current knob, then adjust the high amperage using the Peak Current knob, Clean Area Width (start at around 30%), Post Flow 5-10 seconds.

DC TIG - Select TIG, DC, Pulse Mode off (flat line), desired amps using Basic Current knob, Post Flow 5-10 seconds.

DC TIG Pulse - Select TIG, DC, Pulse Mode on (square wave), set Peak Current to 0, then the desired low amperage using the Basic Current knob, then adjust the high amperage using the Peak Current knob, Post Flow 5-10 seconds,. Set pulse controls as desired: Pulse Frequency, Pulse Duty.

TIG Operation and Principles
Shielding Gas. Use 100% Argon at 15-25 CFH (cubic feet per hour). Use higher flow when extending the tungsten electrode to reach into corners or gaps. Set 65 psi air pressure at the regulator for plasma cutting.

Tungsten Electrode. Ceriated tungsten (grey or orange) is recommended by Longevity. Use smaller diameter electrodes for thinner metal (low amperage), thicker electrodes for thicker metals that require more amperage. If you melt an electrode step up to a larger electrode. When using higher Clean Area Width settings in AC mode, a thicker electrode will be required due to more heat moving into the electrode.

Before any welding takes place, it is necessary to put on protective gear and familiarize yourself with safety precautions. TIG welding is an elite form of welding. Not many people learn to fully master the technique due to the patience and practice this art form requires. This manual cannot make you a good welder. Only practice and skill can do that.

The shielding gas flows out from the torch head to cool and protect the molten puddle and the tungsten as the arc continues to melt the base metal. As the metal melts and a circular puddle is formed, the Tig torch is slowly moved forward. While the metal gently flows together, the filler rod is kept near the arc and in the gas cone to keep it hot and keep it from oxidizing. As the metal begins to form a "keyhole" shaped puddle and penetration of the metal is achieved, the filler rod is gently added to the molten puddle and then removed as a molten drop of filler material is added to the base material.

As you familiarize yourself with the above digest of basic TIG welding, there are a couple of basic knowledge items that need to be addressed. The tungsten must be shaped prior to initiating an arc. With inverter based TIG welders, tungsten sharpness is important. Refer to the following diagram to correctly sharpen a Tungsten electrode. Notice the incorrect way of sharpening an electrode. Radially sharpening an electrode will cause an unstable, wandering arc, making it difficult to control the weld puddle. Carefully rotate the tungsten as it is being ground to prevent a flat spot or a hollow ground point. Also note that tapering the tungsten to 2.5 X’s of its diameter is generally recommended for most DC welding applications. For higher amperage DC welding, do not over sharpen the point, but leave a slight truncation on the end of the electrode. This prevents the tungsten tip from breaking away and falling into the weld. When AC welding, a small ball may form. This is normal. However, if a large globular ball begins to form, resharpen the tungsten and adjust the AC balance. It is also normal for a slight dome to form on the tungsten in DC mode. However, if the arc becomes erratic or the arc is difficult to start, regrinding will be necessary. If the tungsten is accidentally dipped into the weld puddle, regrind the tungsten, particularly on aluminum. Grind tungstens only on a dedicated stone, free of contamination from other metals. Hand held tungsten grinders usually grind perfect points. Once the tungsten has been sharpened, install it into the torch.

Filler Rod Selection. Depending upon the metal to be welded, filler rod selection is critical. Consult with your local welding supplier for the optimum filler rod to properly complete the weld. In certain applications, TIG welding can be performed without the use of a filler rod. Use a 5356 filler rod for Aluminum.

Beginning the TIG weld. One of the biggest issues for beginning welders is holding and maintaining an arc. Starting an arc with your High Frequency welder is quite simple. Select the machine for TIG operation. Then, select the desired amperage. Grip the torch in a manner that is comfortable to you. (Many skilled welders use an underhanded grip to steady themselves on the metal.) Place the torch so that the tungsten is no more than 1/8 inch from the weld surface. Depending upon the setup, either press the foot pedal down or touch the torch and hold (2T setting) the trigger to initiate the high frequency arc. A small blue glowing cone may be observed. This is the high frequency arc. Immediately after that, you should see a strong, stable arc flowing from the torch. As the arc begins to grow, a molten puddle will appear. If it does not appear, stop welding and increase the amperage. Repeat the start sequence.

1. To help the molten puddle form, slowly make small circles with the torch to build the heat in the weld area. A bright, fluid puddle will begin to form.

2. Once a uniform puddle is established, tilt the torch head about 75 degrees from the weld surface into the direction of the weld. This will direct the arc to the front of the weld puddle.

3. Grip the filler rod at a 15 degree angle to the weld surface with the other hand. Hold the rod in the iridescent cone of gas that surrounds the weld puddle. Do not hold it in the arc. Keep it close to the weld. A "skeleton" keyhole will begin to form in front of the weld. The keyhole is evidence that you are ready to add filler material and move forward. Introduce the filler rod into the key hole area underneath the arc. Wait for a single molten drop to fall off the tip of the rod.

4. When a molten drop falls from the rod, quickly remove the rod, keeping it inside the gas cone. The molten drop of filler metal should blend quickly into the puddle.

5. Move the torch forward slightly, carrying the keyhole with the weld. If the key hole is lost, then forward travel was too fast or too far. When the keyhole shows good development, repeat the steps 3-5 until you have a proper weld bead established.

6. Weld termination. When the weld bead has reached the desired length, add a final drop of filler and slowly circle the torch over the end of the weld to fill the crater. If the weld crater is not correctly filled, cracking and weld failure may occur. This is a small but important step to properly completing a weld. Release the foot pedal or release the trigger to stop.

09-12-2009, 11:25 AM
LS-200P Operation
MMA/Stick Welding (SMAW)

DC Stick - Select Stick, DC, desired amps using Basic Current knob, desired Arc Force, Pulse Mode off (flat line).

AC Stick - (Aluminum) Select Stick, AC, desired amps using Basic Current knob, desired Arc Force, Pulse Mode off (flat line), Clean Area Width (start at around 30%)

1. Insert electrode into electrode holder. Position the electrode for the most comfortable position so that the electrode can be held directly over the work piece with a slight angle.

2. Set Amperage to the recommended amperage by the electrode manufacturer. Strike an arc by swiping it briskly across the work piece in the same manner as one would strike a match. Alternatively, you may strike an arc with firm tapping motion against the work piece. Either method is acceptable. An arc should initiate. Continue to keep the arc going by holding the electrode off the work piece no more than the electrode width.

3. Continue the arc by feeding the electrode into the weld puddle while moving the electrode forward. This will take some coordination, but will be fairly easy to do after practice. Do not allow the arc to become too long, because air and slag can become entrapped in the metal. The sound of a proper arc will be similar to a gentle frying sound. A long arc will emit a humming sound. An arc that is too short may be extinguished and the electrode may stick to the work piece. If the electrode sticks, immediately release the electrode from the electrode holder and break the electrode loose by hand. If the flux breaks off, simply trim off the ex-cess rod until flux and bare metal meet. A welding rod must have flux to shield the weld from the atmosphere or the weld will fail.

4. Use the Arc force and Amp adjustment to change arc qualities. Adjust the amperage according to the recommendations of the electrode (welding rod) manufacturer for the type and size of the electrode used.
The arc force will affect how crisp the arc is whether it is smooth and buttery or deeply penetrating. Use it to suit the desired weld finish. Experimentation will be required to find the optimal setting desired. It is an excellent tool for out of position welding.

5. Electrode selection. Electrodes are usually given performance and characteristic ratings using a system of letters and numbers determined by the American Welding Society (AWS). The rating system includes the minimum tensile strength of the finished weld, the weld position (flat, vertical, horizontal, or overhead or a combination of two or more positions) and the flux type. Additional information may be given. Each manufacturer has their individual name and terminology as well. As there is no general recommendation that can be made about a particular electrode selection, except for practice welds, a electrode designated by the AWS as E 6011, E 6013, E 7014, or E 7018 may be used, each having its own distinct features and purpose. These are among the most common electrodes used in the industry and are not difficult to find. E 6011 electrodes are not as smooth running as some of the other electrodes, but offer the advantage of being able to weld on rusty metal and contaminated surfaces. It is widely used and requires very little skill to begin using. This is not a particular endorsement of an E6011, rather a simple example of what may be used in developing proficient technique. It is recommended that a variety of electrodes be used and practiced with. Consultation with an experienced local welding supplier will help greatly in determining what welding electrode is the best for your given situation. Many times, samples or small packages of electrodes are available at relatively low cost to determine for yourself the best electrode to use.

Stick Electrode Chart Example: E 60 1 3Strength
60--60,000 psi,
70--70,000 psi
Weld Position
1--All positions: Flat, Vertical, Horizontal, & Overhead
2--Flat Position or Horizontal Fillets Only
3--Flat Position Only
Weld Characteristics
0--Non-low hydrogen, DC Reverse polarity
1--Non-low hydrogen, AC or DC Reverse polarity
2--Non-low hydrogen, AC or DC Straight polarity
3--Non-low hydrogen, AC or DC Either polarity
4--Non-low hydrogen, iron powder coating, AC or DC Reverse polarity
5--Low-hydrogen, DC Reverse polarity
6--Low-hydrogen, AC or DC Reverse polarity
7--Non-low hydrogen, iron powder coating, AC or DC Reverse polarity
8--Low hydrogen, iron powder coating, AC or DC Reverse polarity
Polarity Definition
electrode negative =straight polarity (typical stock machine setup)
electrode positive =reverse polairty

Be sure to observe the electrode manufacturer recommendations regarding polarity. If the weld appears lumpy, porous or otherwise malformed, change the polarity of the ground cable and the electrode holder cable. Many electrodes run with in reverse polarity, (DCEP) setting. A few run with a straight polarity (DCEN). Some will run either way. For reverse polarity (DCEP) stick welding, swap the electrode holder and ground cable connections.

Proper weld identification. Overlap and undercutting are two main causes of weld failure. Proper washing of the weld bead into the sides or "toes" of the weld is important. Keep the welding electrode or the TIG tungsten and welding arc within the weld joint to prevent overlap. Pausing on the sides of the welds to wait for the sides to fill reduces the chance of undercutting, even if the current is a little too high. If it is possible, with any practice weld, cut the joint down the middle, lengthwise, or place the weldment in a vice and use a hammer to bend the metal over the weld area until it is either broken or bent 90 degrees. This destructive testing method will help you improve your skill by revealing faults and flaws in your welds.

09-12-2009, 11:26 AM
LS-200P Machine Operation
Plasma Cutting

Select Plasma, DC, 2T, desired amps using Basic Current knob, Arc Force to max, Post Flow to 5 seconds. Set 65 psi air pressure at the regulator.

Plasma Principles
Before any welding or cutting takes place, it is necessary to put on protective gear and familiarize yourself with safety precautions. Plasma Cutting is an efficient and simple way to cut multiple metal types. The super sonic plasma stream, generated by ionized pressurized air, is capable of rapidly burning metal without overheating the surrounding area. This is helpful for preventing warpage and preventing the formation of Heat Affected Zones (HAZ) in the metal.

Simple and easy steps to cutting correctly

1. Set Amperage and Air pressure to suit the units specifications. Place the torch cutting tip up to 1/8 inch from the work piece to prevent extra wear and blow back of material.

2. Press trigger to begin cutting. Hold torch trigger down to continue cutting in 2T mode. To cut in 4T (Automatic) mode, press trigger to allow arc to start and release trigger to continue cutting. Press the trigger again to stop cutting.

3. Once Plasma stream is established and sparks exit the bottom of the piece of metal being cut, slowly move the torch forward into the cut. Depending upon torch orientation, you may pull, push or move side-to-side to make the cut. Grip the torch only tight enough to keep the trigger pressed. A tight grip will result in uneven cutting. Glide the hand gently across the metal, maintaining a drag style cut or a standoff. Use standoff wheels or ring if necessary on long cuts. If the torch tip sticks or fouls excessively, revert to standoff cutting.

4. Continue cutting following the desired path of cut. Make sure that the sparks are exiting the piece of metal at a 10-15 degree angle. If the sparks are exiting straight down, then the cutting speed is too slow. Increase cutting speed until a change of the spark angle is observed. If excessive slag is building up on the bottom of the metal (more than 1/8 inch) then either increase amperage, travel speed or air pressure. Sometimes excessive slag build up on the bottom of the cut occurs because the machine has reached its severance limit. Occasionally excessive slag can be caused by rusty or contaminated metal. Note that cutting thicknesses posted in the specification page are specifically for mild carbon steel under ideal circumstances. Stainless, Aluminum and other metals have reduced cut ratings. Cutting capacity of these metals are generally 10-20% less than mild steel.

5. Exit the cut by pausing briefly to allow the spark stream to catch up and to be directed straight down. This is usually the most challenging part of the cut because the bottom of the cut needs to be even with the top before exiting or the cut piece will remain stuck to the parent piece of metal. Carefully work the plasma stream to the very edge of the cut.

6. Release the trigger to break the arc in the Standard mode setting. In the Automatic mode setting, repress the trigger and release to discontinue the arc.

Caution! Breaking the arc in the auto mode by lifting the arc away will not satisfactorily terminate the arc and may restart the pilot arc. Precautions must be taken in this mode or serious injury can occur.

7. Allow post/after flow cooling to occur. Post flow will continue for up to a half a minute after the cut is completed. If additional cooling is required because of heavy cutting or extended cutting, switch the post flow switch to "Test" to start manual cooling of the torch. After the torch is sufficiently cooled, return the switch to cutting mode to discontinue the post/after flow cooling cycle.

Helpful Hints for cutting.

1. Make several practice cuts first. Adjust the amperage and air pressure throughout the range to see the effects it has on the cut. Each machine will have a slightly different range or "sweet spot".

2. Use a substantial flat piece of metal to make a long, clean cut. Attempting to cut odd objects or make short cuts cannot really train proper technique. It will also be difficult to ascertain the quality of the cut. Practice Cuts Using Different Settings.

3. Keep torch straight in cut. Do not lean or tilt the torch. The ergonomic design of the plasma torch eases this problem. However, fatigue is a common cause for poor, uneven cuts.

4. Keep consumables checked for wear. Tip wear can decrease cutting capacity and cut quality at an imperceptible rate until cutting ability is significantly affected.


The Plasma function is able to perform light to medium gouging, depending upon the type of metal with the standard cutting tip and electrode. To gouge, simply lower the air pressure until the air pressure light signals low pressure. Allow the air pressure to stabilize and increase the air pressure 5-10 pounds above the warning light threshold.
Lean the torch at a 30-35 degree angle to the work piece and begin to gouge. If you experience problems, experiment with the air pressure to accomplish the desired type of gouge. For certain applications, a special gouging tip may be required.


Occasionally, the need will arise to pierce directly down into a piece of metal to initiate a cut with out the benefit of starting on the edge of the material. This is known as piercing. To pierce, simply start the torch with a 1/8 inch stand-off at the desired spot. If possible, lean the torch at a slight angle so that blowback does not become a problem and will not foul the tip. Make sure that you tilt the torch away from the piece being cut out to prevent marring. Allow the torch to slowly burn its way through the metal. As the torch plasma stream burns down through the plate, straighten the torch into the cutting position. As sparks begin to exit the bottom, you may shorten the standoff and begin your cut. Excessive use of piercing will significantly reduce consumable life, particularly with an inexperienced operator. Do not attempt to pierce an object that is thicker than 50-60% of the rated cut capacity to ensure long torch life.

Note: Piercing can produce a lot of blowback of molten metal. Protective gear is absolutely required, especially face shields and fire proof clothing.

09-12-2009, 02:24 PM
Very helpful Robrob. Thanks for posting.

09-12-2009, 03:10 PM
Lots of good info and a good read, ya always learn something every time you look over stuff like this. One of the best things I have found on these machines to educate yourself is a little tricky but can be done. In tig, pulse mode especially to get the feel for the controls I set up a torch so only one hand(my left in this case) can stay a pretty much standard distance from a plate. Then I adjust each knob on it's full range to see the effect you have on the weld puddle. It becomes pretty obvious when reading it may seem a bit hard to understand. You can pick out the value of frequency, pulse width and see how the pulse current effects it all. Key to learn is the pulse current sets the HIGH amps or current for welding; and the other functions control how long and how often you hit that high current, sort of keeps the puddle cooler and easier on thin stock.

Anyway give it a try, does help. When you get good at that then try the foot pedal, now that's a bit tougher since it takes two hands to hold down the pedal and then adjust the control knob. Gives you a feel for the range you have when you set the knob at a certain level.

Fun stuff...

09-12-2009, 05:07 PM
Here's a basic question, does the Pulse Frequency control change the AC and DC frequency, or just the DC pulse frequency?

And if it does, do any of the rest of the pulse controls change the AC TIG waveform?

09-12-2009, 05:22 PM
Junes may have a better answer as he has more knowledge but from what my testing has shown...

DC Pulse Frequency only impacts DC mode, pulse mode on. Nothing in AC mode or with pulse off.

AC frequency and %clean only function in AC mode; nothing in DC mode.

Pulse Width and Pulse current also only function in DC Pulse mode.

A good way to test all this is to try it. It's sort of fun to set up an arc with one hand and adjust the settings with the other.

In DC Pulse mode you can see...

varying pulse current has no effect unless you have pulse mode on.

varying pulse frequency you can see how the current varies up and down, set the pulse current higher than base current.

pulse width definitely shows how long you are at high current, higher numbers make for a hotter puddle.

hope this helps, lots of expeerimentation is good to learn how it impacts the weld.

09-12-2009, 05:28 PM
Thanks jbman,

That's what I thought but the first post in this thread has some errors:

Square wave/constant wave form?: I assume you want square wave for AC and constant wave form? for DC

Pulse Frequency: Determines the frequency of the AC pulse for welding aluminum, I think faster pulse makes a cleaner weld, slower penetrates more.

basic current: used w/o the foot pedal will limit the AMP to that % of the max out put of the machine use in conjunction with the upslope and down slope dials when using the torch only w/o the foot pedal.

The above three items are incorrect.

Square wave/constant wave form is the DC Pulse Mode switch.
Pulse Frequency only changes the DC Pulse frequency for DC TIG welding.
Basic Current is the base (low amperage) of the DC pulse (bottom of the square wave)

09-12-2009, 05:40 PM
That's what I thought but the first post in this thread has some errors:

Pulse Frequency: Determines the frequency of the AC pulse for welding aluminum, I think faster pulse makes a cleaner weld, slower penetrates more.

basic current: used w/o the foot pedal will limit the AMP to that % of the max out put of the machine use in conjunction with the upslope and down slope dials when using the torch only w/o the foot pedal.

These two descriptions are incorrect.
Reply With Quote

OK: Here's how I understand it...Pulse Frequency above should say AC Frequency, then it would be correct. some machines have this some don't

Pulse Frequency (without AC in the label) is truly DC pulse frequency and only used in DC Pulse mode. Higher pulse actually increases the number of times you will pulse to the higher amperage.

basic current: not sure what that means. without out the foot pedal it sets the amps you weld at, that simple. Upslope gives time before max amps; downslope gives time to wind down amps. when you use basic current with pulse current.....the base current is the low current applied; the pulse current is the high current applied. in this case pulse current should always be set higher than base current

anyway, that's how I understand it now and open for any comments.

---------- Post added at 06:40 PM ---------- Previous post was at 06:34 PM ----------

Caution also: I believe some machines do operate differently. The knobs may have different ranges, or even similiar names with different functions so you really have to check out the specific machine you're on. The comments I made today relate pretty much to the longevity 200PI IGBT welder. the 200P did not have an AC frequency control so frequency in that case would have applied to both DC and AC I just don't recall. So best to check your machine as well, not sure there is a standard out there.

09-12-2009, 06:09 PM
Does anyone know for sure if the Pulse Frequency knob on the LS-200P changes the AC frequency, or is it fixed at the wall outlet frequency of 60Hz?

09-12-2009, 08:44 PM
No the pulse frequency will not change the ac frequency. As for dc it
can't since there is no frequency to adjust in dc. The pulse frequency sets how many times per second the current changes from the high to the low setting. Ac frequency determines how many times a second the current changes from ep to en. So on ac you kind of have pulse on pulse. If you have a low ac frequency say 20hz the puddle will wet really well and be nice and wide or sloppy. If you have a high ac frequency say 250hz the arc is very narrow controlled and tight so easy to control. The main current setting is used for both pulse and no pulse settings this is the highest amps wanted. The low end of the pulse is called the backround current. This is set by either a number setting such as 50amps or a precentage of the basic current. Sorry if this is confusing.

09-12-2009, 09:20 PM

The LS-200 doesn't have an AC Frequency control so I assume it is fixed at 60Hz (USA). For AC TIG we can only change the AC amps and Clean Area Width (AC balance).

My understanding of the Pulse Frequency control is that it only works in DC mode. It's still DC, just a pulsing DC moving from Peak Current down to the Basic (base) Current, but the electrons are still moving only in one direction (DC).

09-12-2009, 09:42 PM
Yes the pulse still works in dc but in one of the posts someone said you can adjust the dc frequency which is imposible you only can change the pulse frequency. If you can not change the ac frequency they it is what ever you have conning out of the wall which in the us is 60hz. You should be able to use pulse on ac as well as dc.

---------- Post added at 03:34 AM ---------- Previous post was at 03:30 AM ----------

Square wave has to do with the ac sinsual wave and is only ac nothing to do with dc. You have no other wave forms other then just dc since there is no wave just a line if that makes any sense. Most new machines are square wave.

---------- Post added at 03:42 AM ---------- Previous post was at 03:34 AM ----------

I saw on one if the posts here that dcep does the pennitration and dcen does the cleaning. This is backwards. You can weld really thick sections on aluminum with dcen and you are able to do this because dcen does the pennitration and dcep does the cleaning. If you have ever had the welder on ep and struck an arc you wl find out really quick that all the heat is going into the tungsten. On trAnsformer machines we sometimes use this to ball the tungsten before welding aluminum

09-12-2009, 09:52 PM

Good catch on the DCEN vs DCEP mixup, I fixed it in the previous post of the front panel instructions.

09-12-2009, 09:56 PM
That really clears it up Junes a lot, sort of confusing using the same words for different things like frequency...but your last note puts it in straight terms, thanks.

09-13-2009, 03:30 PM
It's just the way things Are fequency is a very important part of welding.