Decided to skip the adjustable link on the pedal. All that would do is adjust L arm to pedal distance, which I don't feel is necessary. The idea was to get the rack and cog adjusted to absolute ohm when the pedal is on the its respective stop, but I went ahead and built the rack arm of the L linkage a little longer, so the linkage has 1/8" more throw than it needs, just to be sure.
I can just put a stop screw through a push spring on either end of the rack mount for stops and call it good. The pot has stops in it, but they are only designed to stop an index finger and thumb from cranking it further. I've got my foot on this thing, so I'd rather have the linkage rely on it's own stops, even with a set of pedal down & up stops. The pics don't show the linkage, but I moved the slotted hole down into the bottom hole of the vertical link. It has 3/16" of slide travel, which I think should be enough for the pedal travel to engage the 6-7 and 1-2 switches, before moving the amps.
I'm still waiting on the CK line, transmitter/ receiver and a few odds and ends. I'm going to wait on the rest of the parts to arrive and test the transmitter/ receiver (thanks Rambozo!) before I make the pedal casing.
If I'm using this pedal under low amp conditions and pulsing the pedal, I will be releasing it almost completely. There is a time delay on the gas, but I wonder if I should put a time delay off switch in the 6-7 bridge, or if it matters? I'll see what happens when I connect a micro switch and leads to the 6 and 7 pins to see how responsive it is. If its instant, I won't need a delay to keep it in foot pedal mode. If 6-7 activates a relay or if it's recognized digitally, that may change my mind. I'd rather not wear something out in the welder by having the 6-7 constantly switched, although it may not even be a valid concern.
I think I'm going to put an adjustable light tension ball bearing index on the rack, at the very least, so I can hear and feel an audible click, aside from the micro switches, at min amps before the trigger is released, so I can dip down to min amps for pulsing without losing an arc. I'll just be sure to put a larger bearing in it than the dimple, so my foot has no problem running back out of the index with ease.
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