Powermax 45xp lost arc delay (Solved)

So forgetting about the OP's 7i96 for a moment and focussing on Snowgoer's 7i76 and my 7i76e. give or take an ethernet connection, they are identical.

Both have to use a relay on outputs
I started with a mechanical relay and replaced it with a Mosfet relay a couple of years ago.
Snowgoer started with a Mosfet relay and replaced it with a mechanical relay.

I'm going to assume there is little difference in the triggering of a Hyperthem and Thermal Dynamics machines. After all, they seem to behave the same way if the circuit is active low..

So the question is why does a Mosfet relay work for me and not for Snowgoer on the same circuit.?
The answer has to be the relays are different.

Now robertspark gave us an additional datapoint

robertspark wrote: I've just stuck my ammeter on the PMX45 and this time I got the current rising to about 15.1mA in a little over a minute.

It would be nice to know what the current draw was at the start of that one minute becasue thats the timeframe I'm hearing.

In the same post, Robert also flagged a possible issue in a cryptic way.

robertspark wrote: Load current 0.0025...6 A (i.e. 2.5mA minimum current? .... possible issue??))

So Snowgoers relay has a current range of 2.6 mA to 6 amps
My Relay has a range from 1 mA to 0.5 amps.
I think it can be concluded that my relay is more suited to the task and Snowgoer's is close to that pesky minimum current again which is the "possible issue" Robert was alluding to.

So the 7i76/7i76 spindle relay works for me, why wouldn't it work for snowgoer? That point we don't know yet. I think we need to call upon the test pilot to confirm this

Then we have PhillC switching his 30 amp plasma directly with a 7i96 output

Sorry to be continuing this but there is something here we don't yet understand but we are converging on discovering whats going on.

one thing we have proven is that becasue of my experience, is that some MOSFET relays will work! Its just that you need to choose wisely!

Interference, missing ground, ground loops, wiring ( boards not at the same potential ), etc.
Those are the issues in all of the above, i would hate to see this topic concluding SSR are not good for plasma as that is the way it is going so far, besides Phill and Rod who are using them, but reading the whole topic Rod seems to be against them and for them !?!?!?
SSR are used in all kinds of switching environments, from welders (have one) to high power metal melting furnaces, but plasma is altogether another beast due to so much interference it creates. So i do agree with PCW that using an SSR should work properly.
Normal relays are immune to any interference, so using them is the easy way out, and if everything else works then by all means do use them. Chasing the above mentioned issues can take long and sometimes can not be found with a magnifying glass, but most of the time it is something simple in the wiring causing such hiccups.
Moving the ground clamp to vary the failure rate should have been a very good clue something in the wiring is not OK.

Well don't forget little_sparky, the 7i96 SSR did not work for him either (Everlast 50P) This Post .

And I know you are omitting OP, but it's reasonable at this point (humor me here even though I know you're likely not to agree) to say that he's also not successful with the 7i96 SSR.

Also, it's worth considering that if everyone who is using an SSR (on a MESA card or otherwise) has the ground clamp already on the table, or near by the torch, or permanently affixed to the table, they might not see the full brunt of the issue and are blaming dropped arcs and what not on something else. Ground clamp proximity does play a part in all of this.

tommylight wrote: Interference, missing ground, ground loops, wiring ( boards not at the same potential ), etc.
Those are the issues in all of the above, i would hate to see this topic concluding SSR are not good for plasma as that is the way it is going so far, besides Phill and Rod who are using them, but reading the whole topic Rod seems to be against them and for them !?!?!?
SSR are used in all kinds of switching environments, from welders (have one) to high power metal melting furnaces, but plasma is altogether another beast due to so much interference it creates. So i do agree with PCW that using an SSR should work properly.
Normal relays are immune to any interference, so using them is the easy way out, and if everything else works then by all means do use them. Chasing the above mentioned issues can take long and sometimes can not be found with a magnifying glass, but most of the time it is something simple in the wiring causing such hiccups.
Moving the ground clamp to vary the failure rate should have been a very good clue something in the wiring is not OK.

Yea, I tend to agree there is probably more going on here. For me the thing in the wiring that wasn't ok was the SSR. Was that ultimately a symptom of a larger problem? Probably. That said, I go back to the fact that when the Hypertherm manual calls for dry contact closure; they are looking for a mechanical relay. They describe their internal arc ok relay as "provides dry contact closure" and I know for a 100% fact hypertherm uses a mechanical relay for arc-ok. Did Hypertherm use the wrong technical term? Probably.

That said, I have shielded cables, good grounds, etc.

Should be able to use an appropriate SSR in place of a mechanical relay and can successfully use one are two totally different things. I agree in theory they're better, that's why I tried one. In practice, for me, and a few others, they do not work in this application.

I read everything so i know there are 3 cases by now, pretty sure we are going to see more.
I also know of many more who use 7i96 and 7i76 to fire the torch without issues

snowgoer540 wrote:
Should be able to use an appropriate SSR in place of a mechanical relay and can successfully use one are two totally different things. I agree in theory they're better, that's why I tried one. In practice, for me, and a few others, they do not work in this application.

This totally ignores the fact that I have a SSR that has been working perfectly at firing the torch on my 7i76e ever since I've been using Plasmac.

For some reason, I always thought Snowgoer was using a 7i96 and on this thread I learn he is using a 7i76 and an external relay.
I always thought he had problems with the internal relays of the 7i96. Now I find thats still sitting in his drawer unused!

Snowgoer has also totally ignored the links and evidence from PCW and myself that SSR's also satisfy the dry contact closure criteria.

Now I find (as robertspark pointed out) that the SSR relay Snowgoer used is marginal in terms of the current range.

In this plasma journey we are all on, there are a lot of unknowns and a lot of things still to discover. None of us can afford to have a closed mind. To have one and be vocal about something to an extent that its "my way or the highway" is not helpful as it just provides static and misinformation for those that follow.

There is no evidence provided from Snowgoer that is relevant to the onboard Mesa relays such as the 7i76/7i76e spindle enable or the 7i96 outputs. Any future user must ignore all of what has been said about Mechanical relays as being mandatory for dry contact closure.

There is no evidence yet that the Mesa on board SSR's are unsuited for plasma operations. You cannot take a single data point for an external relay and apply it to Mesa's onboard SSR's.

In fact, there is evidence that people are using the Mesa relays without problems. I'm now one of them as this thread motivated me to get off my backside and use the spindle enable relay.

tommylight wrote: I read everything so i know there are 3 cases by now, pretty sure we are going to see more.

Tommy, I am sure you are right as over time, there have been a number users using the Mesa SSRs. Its just that they are out there cutting away and not following this forum becasue they don't have a problem to solve!

I for one am very happy that I have now eliminated all external relays from my plasma table as it will improve the reliability and MTBF.