New start

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15-03-2018
Nickhofen

Re: New start

Robert in the name of Odin, can you share the schematic, or point the thread? :-)
15-03-2018
Davek0974

Re: New start

Quote:

Originally Posted by Clive S

Do you have soft limits as well? It's all debatable but hitting the limits say while jogging should not (in my opinion) be an E-Stop as it is not an emergency

This is why I would always recommend running soft-limits. IMHO the type of machine decides the limit system used - A stepper drive is safe if it runs away and hits a stop, the steppers will stall so I would forget limits altogether and fit a home switch plus soft limits, nothing more.

On a servo drive, mechanical breakage is very easy so i would fit hard limit switches wired to the servo power/estop circuit contactor, forget the software, just kill the power. Then fit a home switch and use soft limits to ensure you cannot jog into a limit, ever.
15-03-2018
Nr1madman

Re: New start

Quote:

Originally Posted by Davek0974

This is why I would always recommend running soft-limits. IMHO the type of machine decides the limit system used - A stepper drive is safe if it runs away and hits a stop, the steppers will stall so I would forget limits altogether and fit a home switch plus soft limits, nothing more.

On a servo drive, mechanical breakage is very easy so i would fit hard limit switches wired to the servo power/estop circuit contactor, forget the software, just kill the power. Then fit a home switch and use soft limits to ensure you cannot jog into a limit, ever.

Aha! Good reasoning :)
Then I feel safe with my steppers!
Limits to the bob only and no messing with e stop!

Thanks :D

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15-03-2018
Nr1madman

Re: New start

Quote:

Originally Posted by Nickhofen

Robert in the name of Odin, can you share the schematic, or point the thread? :-)

Haha I stole this one https://image.ibb.co/jthYfG/tapatalk_1511816242127.jpg

Mostly what I'm aiming for but slight modification.
Have routed the enable signal straight through the main relay instead of using two relays.
Have not understood the logic of using two relays yet..

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15-03-2018
JAZZCNC

Re: New start

Quote:

Originally Posted by Desertboy

UC have a USB or ethernet solution, Jazz was comparing using a PC with PP for step generation. UC cards are step generators. It gets confusing because like me nr1madman is using a cheap PP BOB to connect to the steppers, switches etc.

but the connection to the PP BOB is running a lot faster than if it was a PC PP. A few people have warned that using that cheap board will limit upper performance but I was told you will be able to run at least 50khz per axis with that cheap board connected to a step generator if you need more you need a better breakout board. For my Mesa card it's £100 for the better BOB so I'm happy to use my existing BOB for now and 50khz is actually a lot depending how you set microstepping.

There's more to it than just speed. Best way to I can relate it is to compare to HIGH end HI-FI Amplifier. You wouldn't dream of fitting cheap speakers to quality Hi-Fi because it would just degrade the sound and make it sound rubbish.

Cheap BOB is just like cheap speakers, your putting clean quality pulses in and the rubbish circuitry is degrading what comes out. Still comes out at same or similar speed but now it's all noisy and crackly.! . . . . Defeats the point of External controller..IMO.

The quality of the pulses you put into drive directly affects how smooth the motors work and it's clear to hear the difference when have bad setup.
15-03-2018
Nr1madman

Re: New start

Quote:

Originally Posted by JAZZCNC

There's more to it than just speed. Best way to I can relate it is to compare to HIGH end HI-FI Amplifier. You wouldn't dream of fitting cheap speakers to quality Hi-Fi because it would just degrade the sound and make it sound rubbish.

Cheap BOB is just like cheap speakers, your putting clean quality pulses in and the rubbish circuitry is degrading what comes out. Still comes out at same or similar speed but now it's all noisy and crackly.! . . . . Defeats the point of External controller..IMO.

The quality of the pulses you put into drive directly affects how smooth the motors work and it's clear to hear the difference when have bad setup.

Thanks!
That was a good explanation..
I guess that's why a good bob costs 50 times more :)

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15-03-2018
JAZZCNC

Re: New start

Quote:

Originally Posted by Nr1madman

Haha I stole this one

Mostly what I'm aiming for but slight modification.
Have routed the enable signal straight through the main relay instead of using two relays.
Have not understood the logic of using two relays yet..

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Where did you find that because I'm sure that's one I've drawn up in the past for someone or modified version of it.! . . . . .Not bothered that you have it just curious where or how it got there.!
15-03-2018
Nr1madman

Re: New start

Quote:

Originally Posted by JAZZCNC

Where did you find that because I'm sure that's one I've drawn up in the past for someone or modified version of it.! . . . . .Not bothered that you have it just curious where or how it got there.!

Its in the forum, think the user is euricain?

I was thinking about using a much simpler schematic from you but this appealed to me.
Routercnc has posted a schematic aswell that I've studied. It too has advantages!
Since I'm feeding the stepper drivers with ac I dont need the bleeding resistor for the capacitance bank that routercnc had incorporated..

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15-03-2018
Desertboy

Re: New start

Quote:

Originally Posted by Nr1madman

Thanks!
That was a good explanation..
I guess that's why a good bob costs 50 times more :)

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After reading Jazz's post I've took the plunge with a 7i76 BOB for my Mesa in the end it cost £140 delivered so that estimate was pretty close lol as my PP BOB cost £3.

http://store.mesanet.com/index.php?r...product_id=119

I'm sure UC must have equiv you might even be able to use this board lol.

For reference it's cost £250 for the complete mesa controller, pci card + bob with high quality cabling.
15-03-2018
Nr1madman

Re: New start

Quote:

Originally Posted by Desertboy

After reading Jazz's post I've took the plunge with a 7i76 BOB for my Mesa in the end it cost £140 delivered so that estimate was pretty close lol as my PP BOB cost £3.

http://store.mesanet.com/index.php?r...product_id=119

I'm sure UC must have equiv you might even be able to use this board lol.

For reference it's cost £250 for the complete mesa controller, pci card + bob with high quality cabling.

I'm sure the mesa boards are top quality but that would mean Linux?

Not for me my friend :D

Is fusion360 still free?
Seems like only for students now?

Tried estlcam now this evening and it seems basic but powerful !
Anyone tried it?
Or should I hold on with the software and focus on getting movement first ;)

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