Hall effect proximity sensors

[the great waldo]

I was just asking for general advice rather than for a specific device - but likely something like the NJK-5001C

Hi Voicecoil
I'm not sure if you checked your original post but you wrote "I'm thinking of using these for homing sensors" however "these" didn`t refer to anything, so a sensible reply would have been difficult. Maybe this was just a typo ?
Cheers
Andrew

[Voicecoil]

Hi Voicecoil
I'm not sure if you checked your original post but you wrote "I'm thinking of using these for homing sensors" however "these" didn`t refer to anything, so a sensible reply would have been difficult. Maybe this was just a typo ?
Cheers
Andrew

"These" referred to the title of the thread.......

[the great waldo]

Ahh

Ok I got it.

Cheers
Andrew

[cropwell]

https://www.google.co.uk/url?sa=t&rc...DWNnAf7sglZ7fP

Page 64

But I personally would stick to Inductive sensors.

[magicniner]

2 inductive sensors in series on each axis, one sensing the linear position and one sensing a rotating tab or chopper on the ball screw or stepper would give you accurate, repeatable homing.

[Voicecoil]

2 inductive sensors in series on each axis, one sensing the linear position and one sensing a rotating tab or chopper on the ball screw or stepper would give you accurate, repeatable homing.

Having a rotating tab on the ballscrew is a good idea - essentially magnifies the resolution - I'll see if there's room to incorporate it.

[cropwell]

2 inductive sensors in series on each axis, one sensing the linear position and one sensing a rotating tab or chopper on the ball screw or stepper would give you accurate, repeatable homing.

I presume these would have to be the Normally Open types. I think it is over the top for woodwork, but probably OK for watchmaking.

[magicniner]

I presume these would have to be the Normally Open types. I think it is over the top for woodwork, but probably OK for watchmaking.

Series for NO, so the circuit only closes when both close.
Parallel for NC, so the circuit only opens when both open.
:D

I'm planning this with my Chester Mill CNC conversion, I've become accustomed to being able to shut down my X7 and know there will be no positional errors when I turn it on the next day, select the WCS and slot a part into a fixture, I can't imagine going back to having to indicate every time I fire a machine up, I don't think a homing system which requires you to re-indicate a fixture which hasn't been moved is acceptable, in fact I think that's the definition of Useless.

[johnsattuk]

2 inductive sensors in series on each axis, one sensing the linear position and one sensing a rotating tab or chopper on the ball screw or stepper would give you accurate, repeatable homing.

Generally I don't use N/O types for limit switches, they dont cover broken connections. Could use two N/C in parallel

[Voicecoil]

Generally I don't use N/O types for limit switches, they dont cover broken connections. Could use two N/C in parallel

Equally well, N/C types don't cover short circuits, had a few of those in my time....