E stop configure

[Evans]

I'm intending to control my spindle directly from it's supply rather than use my software.
To shut down my CNC I'm thinking to put my emergency stop in the mains supply to the spindle and CNC machine
but not to my computer.
Is this going to work ?
Since my spindle control and electronics will be separate it looks on paper
to be a way of shutting everything down.

[JohnHaine]

My lathe has a vfd which can't be speed controlled from the cnc. I have wired the standard no volt contactor in series so hitting the stop button just removes mains from the vfd which stops the spindle quickly. I also have a mains isolating device connected to the vfd input which outputs an open collector logic level to the estop input to halt axis movement. So this leaves the controller running but just in the estopped state so I don't have to reinitialise it and reload gcode and stuff. This works fine.

[Lee Roberts]

However, it should be noted that it is strongly advised NOT TO remove power from a VFD when/if the spindle is still spinning, this can damage your VFD and/or spindle....

[JohnHaine]

However, it should be noted that it is strongly advised NOT TO remove power from a VFD when/if the spindle is still spinning, this can damage your VFD and/or spindle....

So what happens on a power outage?

[Evans]

I've attached a photo of my CNC machine as you can see controlling the spindle from it's independent unit will be easy,

I'm all for keeping things simple. I can control the spindle speed and stop start from it. I'm an experienced furniture maker.
Thinking it through I can't see a delay in stopping the spindle would be problematic.

So to emergency stop the rest of the CNC operation would running the E stop through the AXBB-E unit be best ?

Another question is what protection would be advisable in my electronics enclosure, circuit breakers or similar.
I'm most interested in protecting the AXBB-E unit and drivers.
So perhaps something basic to the power supplies and something more exotic to the electronic units ?

[Evans]

The whole issue with electronics and computers is so complex that getting definite answers rather than opinions is difficult.
I'm building on a budget so need to be aware of what is peripheral and what are necessary precautions.

Shielded cables and grounding the chassis does seem to be a necessity to prevent problems later.

An emergency stop facility, limit switches and circuit protection also are in the necessary folder.

That said I want to keep it simple so I'm trying to find the compromise between necessity and unnecessary componentry.
Thanks for the responses Evans

[phill05]

The whole issue with electronics and computers is so complex that getting definite answers ( there are thousands if not more making electronic components so you cannot get a definite answer each cnc builder can only give you their advice/opinion) rather than opinions is difficult.
(Ask ten different people the same question and you might get 12 different answers)

I'm building on a budget so need to be aware of what is peripheral and what are necessary precautions.

Shielded cables and grounding the chassis does seem to be a necessity to prevent problems later.

An emergency stop facility, limit switches and circuit protection also are in the necessary folder.

That said I want to keep it simple so I'm trying to find the compromise between necessity and unnecessary componentry.
Thanks for the responses Evans

[phill05]

I'm intending to control my spindle directly from it's supply rather than use my software.

No problem in doing that I do that with one of mine (it goes without saying" the only thing is you have to Remember is to turn it on before you hit the go button.

To shut down my CNC I'm thinking to put my emergency stop in the mains supply to the (not the spindle you have that under your own finger control) CNC machine
but not to my computer.

Is this going to work ? See in red

Since my spindle control and electronics will be separate it looks on paper
to be a way of shutting everything down.