I have a Miller synchrowave 250 DX that I plan to add a sequencer and
pulser to. In reading all of the posts on Millers two styles of
remote contactor and current control add ons over the past two years,
and value. Is there a better alternative?? I am using a Tec Torch
SW320 water cooled torch and I like it a lot. I have been doing more
out of position automotive welding lately, and holding the pedal
between my knees is getting old.
I don't ming building stuff if that is the way to get the best gear
but my goal is to weld, not build gear.
For my 250DX I just use tiny contact buttons electrical taped to the
Itr makes for a really compact size and you can rotate the handle tube
to position the switch.
The buttons I use are standard OEM replacement buttons for plasma
The button is sealed in black silicon rubber, so you won't get a shock
from it if the switch wires pick up some high-freq bleed thru.
I get them from a local welding repair shop for about $20 each.
You can either buy another 14-pin amphenol connector for it or take a
cheaper route and add in a connector set on your foot pedal cable so
you can brake that cable and connect your button contactor to it.
The foot pedal uses 5 pins (A, B, C, D, and E)
The conactor only uses 2 (A+B).
When running wires for a contactor controller back along the torch
cable, make sure too use shielded wires to help fight high freq
BTW to access the sequencer settings you have to set the amperage
control to "panel" first.
The up and down slope controls don't activate until you turn them up
On Fri, 31 Dec 2004 12:32:47 GMT, Ernie Leimkuhler
I looked at your photo in the metalworking archives, the button looks
like a Miller part (?) and I am sold on the idea of the sequencer.
However, is having amperage control that useful or is just setting the
values at the panel all that I need? From the complaints about how
hard it is to use the _north-south_ amp controls in the archives I am
beginning to wonder how useful the remote amperage control is.
Some people really like torch mounted controllers.
Personally anything bigger than a small button makes my hand cramp
trying to reach around it.
A sequencer is so much more elegant.
The core of it is having an idea of your amperage need for each job,
and if you have some scrap pieces nearby , it is quite easy to figure
that out through trial and error.
The basic amperage rules give you your range.
Here is a past response I wrote about setting the dials.
Subject: Re: Pulser & Sequencer
Date: Wed, Aug 6, 2003 2:10 PM
From past posts of mine:
A pulser is a device used to interrupt a welding arc.
Mostly used on TIG, but can also be used for MIG.
The idea is to cycle the arc from high amperage to low amperage.
The metal melts at the high amperage and solidifies at the low amperage.
There are 3 settings for a pulser.
1. Background amperage
This sets the low amperage and is usually set as a percentage of the
So if you main amperage is 100 amps, and the Background Amperage is set
for 50%, then you Background Amperage is 50 amps.
2. Percentage of On time.
This sets how much of each pulse cycle is spent at the high amperage
and how much a the low level, once again by percentage.
A setting of 50% evenly splits the cycle between low and high amperages.
Less than 50% on On time gives a Spikier Pulse.
Greater than 50% gives a Softer Pulse.
3. Cycles per second.
This is the really confusing one, because it has the most profound
Older TIG pulsers only allow up to a maximum of 10, or less, Cycles Per
Second (Hertz - Hz), but the newer Inverter TIGs allow much higher
My Maxstar 200DX goes up to 200hz.
The lower pulse frequencies are for traditional pulser use, where you
run between 1 and 2 hz on the pulse. adding filler metal on every pulse
or every other pulse as you progress across the weld.
The higher frequencies have a much different effect, in that they tend
to make the metal super-liquid, allowing it to flow and wet out much
These higher settings work very well with autogenous welds where no
filler metal is added at all.
These are also called Fusion or Flow welds.
I also found these higher frequencies worked well for vertical welds in
heavy Silicon Bronze.
Now the reason for all this pulsing is rather simple.
Lets start with a piece of 16 ga steel.
At 0.062" thick the proper amperage would be 1 amp per 0.001" of
thickness or 62 amps, for a flat-butt weld, full penetration, single
You could easily TIG weld a seam in 16 ga Steel using a continuous 62
However a spike of high amperage will melt the metal much faster than a
low amperage, so you could weld faster at 80 amps than 62 amps, but at
that heat you risk overheating the metal and causing undue warpage or
burning of the steel, so you mix an interval of 80 amps with an
interval at 40 amps.
The low amperage interval allows the puddle to solidify back into steel,
without allowing the arc to break.
By pulsing the weld across the bead you get a very orderly row of
rings, that give that distinct stack-of-dimes look to the weld bead.
You adjust the exact pulse frequency to suit your style and speed of
welding as well as the thickness of the metal.
The other benefit is that over all, you have put less heat into the
metal, so you have less distortion.
A smaller, consistent weld bead is often stronger than a larger
inconsistent weld bead.
The more consistent a weld is the more the stresses apply along it's
Any peak or valley in a weld becomes a stress point for failure to
Whether you choose to add filler metal on every pulse, every other
pulse, every third pulse or not at all is dependent upon your own
welding style and the
circumstances of the weld.
Where pulsers become bewildering is when you start messing with the
percentage settings for the Background Amperage and percentage of On
The number of possible combinations is huge, and there is little or no
guidance given in the welding world as to application.
Pro-Fusion has an excellent series of webpages with online calculators
that allow you to punch in the overall required amperage you want and
how fast you want to weld and it will generate pulser settings for you.
It still gives no guidance as to when you want a Spike pulse, or a Soft
pulse, but it gives you something to play with.
50%, 50% and 1.4hz, is a setting that works for most sheet metal.
All I can say is that until somebody puts out some really authoritative
research showing what pulser settings are best for what combination of
weld and materiel, we will all be out there experimenting on our own.
I have searched for such a book for 5 years, and given up.
Hopefully some day soon the welding engineers will decide to enlighten
us lowly welders.
The guideline I can give you is that the thinner the materiel the more
it benefits from a spikier pulse.
I have yet to find a benefit to a really soft pulse.
An example of an extreme spike pulse is that you can weld a popcan at
as long as you set your pulser to 2% On Time and 2% background amps.
Subject: Re: New Maxstar 200 DX ... Setup?
Date: Sat, Nov 30, 2002 10:46 PM
What does a sequencer do?
Well pretty much everything except make your coffee.
A sequencer is gods gift to repetitive welding jobs.
Most machines with sequencers have this series of events that are
controlled by it.
This sequence is initiated by one button tap.
1. Preflow gas - This will purge air from the line and torch before the
2. Arc initiation via high frequency.
3. Initial Amperage - This is the amperage the machine starts at once
the arc is initiated.
4. Up Slope - this is the amount of time the machine takes to ramp up
from the initial amperage to the working amperage.
5. Working amperage - the amperage needed to weld the materiel.
5. Pulsed weld amperage.
Then a second button tap when the weld bead is complete.
6 Down Slope - the time it takes to get from the working amperage to
the final amperage.
A longer down slope prevents a pit from forming in the end of the weld
7. Final amperage - what the machine slopes down to before terminating
8. Post flow gas - This shields the tungsten and weld area as both cool.
So all that with just 2 button taps.
To give you an idea of settings, my machine is currently set up for
tack welding together stainless steel picket railings.
1/2 second preflow gas, 2 amps initial amperage, 1 second up slope, 80
amps working amperage, pulser is set to 40% on time, 50% background
amperage and 1.8 pulses per second, 3 seconds of downslope to a final
amperage of 3 amps and 10 seconds or postflow.
I adjust the working amperage a little up or down depending on how the
welds are going.
The main challenge of using a sequencer is figuring out what amperage
you really NEED to weld a bead.
Trial and error can get you there.
Here are some guidelines for minimum amperages.
Start with 1 amp for each thousandth of an Inch of thickness (0.001").
So 1/8" steel or aluminum = 0.125" thick = 125 amps.
Simple and easy.
Now 2 complications.
For inside fillet welds, increase amperage by 30%
For outside fillet welds, decrease amperage by 30%
Those numbers are for Steel or Aluminum.
For stainless steel, decrease amperage by 30%.
For copper, increase amperage by 100%.
For bronze, decrease amperage by 50%.
Ernie: Many Thanks.
I'll go with the contactor and the sequencer/pulser boards.
I never cease to be amazed by the wealth of knowlege and willingness
to share on this forum.
Best of the New Year to all.
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